William Karlsson got his third career hat trick, Shea Theodore scored in overtime and the Vegas Golden Knights extended their winning streak to a season-high six games with a 6-5 victory over the Anaheim Ducks on Sunday night.

Theodore's winner 3:50 into OT came after the Golden Knights squandered a two-goal lead late in the third period. Mark Stone picked up his fourth assist on Theodore's goal.

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Vegas Golden Knights center Patrick Brown (38) scores past Anaheim Ducks goaltender John Gibson during the first period of an NHL hockey game in Anaheim, Calif., Sunday, Feb. 23, 2020. (AP PhotoChris Carlson)

William Karlsson got his third career hat trick, Shea Theodore scored in overtime and the Vegas Golden Knights extended their winning streak to a season-high six games with a 6-5 victory over the Anaheim Ducks on Sunday night.
Anaheim Ducks goaltender John Gibson, right, blocks a shot by Vegas Golden Knights center Paul Stastny during the first period of an NHL hockey game in Anaheim, Calif., Sunday, Feb. 23, 2020. (AP PhotoChris Carlson)

Henrique brought the Ducks within a goal with 2:57 remaining when he knocked in a rebound after Nick Ritchie was stopped by Vegas' Malcolm Subban, then sent it to overtime with 1:15 remaining when the Ducks crashed the net.
Vegas Golden Knights center Patrick Brown, left, checks Anaheim Ducks defenseman Jacob Larsson during the first period of an NHL hockey game in Anaheim, Calif., Sunday, Feb. 23, 2020. (AP PhotoChris Carlson)

Patrick Brown also scored and Subban made 25 saves for the Pacific Division-leading Golden Knights.
Vegas Golden Knights center Patrick Brown, right, celebrates with defenseman Nick Holden, left, after scoring during the first period of an NHL hockey game against the Anaheim Ducks in Anaheim, Calif., Sunday, Feb. 23, 2020. (AP PhotoChris Carlson)

The Ducks evened it with 1.3 seconds remaining in the first when Shore was in the high slot and redirected Brendan Guhle's slap shot. Half of Shore's four goals this season have come against Vegas.
Anaheim Ducks center Devin Shore celebrates after scoring against the Vegas Golden Knights during the first period of an NHL hockey game in Anaheim, Calif., Sunday, Feb. 23, 2020. (AP PhotoChris Carlson)

NOTES: All of Karlsson's hat tricks have come with Vegas. The other two occurred during the 2017-18 season. ... Anaheim C Derek Grant, who could be dealt before Monday's trade deadline, was a healthy scratch.
Vegas Golden Knights center William Karlsson (71) celebrates after his hat trick against the Anaheim Ducks during the third period of an NHL hockey game in Anaheim, Calif., Sunday, Feb. 23, 2020. (AP PhotoChris Carlson)

Ducks: Host the Edmonton Oilers on Tuesday.
Anaheim Ducks goaltender John Gibson reacts after giving up the game winning goal to Vegas Golden Knights defenseman Shea Theodore during overtime in an NHL hockey game in Anaheim, Calif., Sunday, Feb. 23, 2020.The Golden Knights won 6-5. (AP PhotoChris Carlson)

Anaheim Ducks goaltender John Gibson reacts after giving up the game winning goal to Vegas Golden Knights defenseman Shea Theodore during overtime in an NHL hockey game in Anaheim, Calif., Sunday, Feb. 23, 2020.The Golden Knights won 6-5. (AP PhotoChris Carlson)
Vegas Golden Knights defenseman Shea Theodore, right, scores the game winning goal past Anaheim Ducks goaltender John Gibson during overtime in an NHL hockey game in Anaheim, Calif., Sunday, Feb. 23, 2020.The Golden Knights won 6-5. (AP PhotoChris Carlson)

Vegas Golden Knights defenseman Shea Theodore, right, scores the game winning goal past Anaheim Ducks goaltender John Gibson during overtime in an NHL hockey game in Anaheim, Calif., Sunday, Feb. 23, 2020.The Golden Knights won 6-5. (AP PhotoChris Carlson)
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Vegas Golden Knights center Patrick Brown (38) scores past Anaheim Ducks goaltender John Gibson during the first period of an NHL hockey game in Anaheim, Calif., Sunday, Feb. 23, 2020. (AP PhotoChris Carlson)

William Karlsson got his third career hat trick, Shea Theodore scored in overtime and the Vegas Golden Knights extended their winning streak to a season-high six games with a 6-5 victory over the Anaheim Ducks on Sunday night.

Anaheim Ducks goaltender John Gibson, right, blocks a shot by Vegas Golden Knights center Paul Stastny during the first period of an NHL hockey game in Anaheim, Calif., Sunday, Feb. 23, 2020. (AP PhotoChris Carlson)

Henrique brought the Ducks within a goal with 2:57 remaining when he knocked in a rebound after Nick Ritchie was stopped by Vegas' Malcolm Subban, then sent it to overtime with 1:15 remaining when the Ducks crashed the net.

Vegas Golden Knights center Patrick Brown, left, checks Anaheim Ducks defenseman Jacob Larsson during the first period of an NHL hockey game in Anaheim, Calif., Sunday, Feb. 23, 2020. (AP PhotoChris Carlson)

Patrick Brown also scored and Subban made 25 saves for the Pacific Division-leading Golden Knights.

Vegas Golden Knights center Patrick Brown, right, celebrates with defenseman Nick Holden, left, after scoring during the first period of an NHL hockey game against the Anaheim Ducks in Anaheim, Calif., Sunday, Feb. 23, 2020. (AP PhotoChris Carlson)

The Ducks evened it with 1.3 seconds remaining in the first when Shore was in the high slot and redirected Brendan Guhle's slap shot. Half of Shore's four goals this season have come against Vegas.

Anaheim Ducks center Devin Shore celebrates after scoring against the Vegas Golden Knights during the first period of an NHL hockey game in Anaheim, Calif., Sunday, Feb. 23, 2020. (AP PhotoChris Carlson)

NOTES: All of Karlsson's hat tricks have come with Vegas. The other two occurred during the 2017-18 season. ... Anaheim C Derek Grant, who could be dealt before Monday's trade deadline, was a healthy scratch.

Vegas Golden Knights center William Karlsson (71) celebrates after his hat trick against the Anaheim Ducks during the third period of an NHL hockey game in Anaheim, Calif., Sunday, Feb. 23, 2020. (AP PhotoChris Carlson)

Ducks: Host the Edmonton Oilers on Tuesday.

Anaheim Ducks goaltender John Gibson reacts after giving up the game winning goal to Vegas Golden Knights defenseman Shea Theodore during overtime in an NHL hockey game in Anaheim, Calif., Sunday, Feb. 23, 2020.The Golden Knights won 6-5. (AP PhotoChris Carlson)

Anaheim Ducks goaltender John Gibson reacts after giving up the game winning goal to Vegas Golden Knights defenseman Shea Theodore during overtime in an NHL hockey game in Anaheim, Calif., Sunday, Feb. 23, 2020.The Golden Knights won 6-5. (AP PhotoChris Carlson)

Vegas Golden Knights defenseman Shea Theodore, right, scores the game winning goal past Anaheim Ducks goaltender John Gibson during overtime in an NHL hockey game in Anaheim, Calif., Sunday, Feb. 23, 2020.The Golden Knights won 6-5. (AP PhotoChris Carlson)

Vegas Golden Knights defenseman Shea Theodore, right, scores the game winning goal past Anaheim Ducks goaltender John Gibson during overtime in an NHL hockey game in Anaheim, Calif., Sunday, Feb. 23, 2020.The Golden Knights won 6-5. (AP PhotoChris Carlson)

Vegas' 5-3 lead appeared safe until Adam Henrique forced overtime with goals 1:42 apart. Both came when the Ducks brought on the extra attacker.

Vegas Golden Knights center Patrick Brown (38) scores past Anaheim Ducks goaltender John Gibson during the first period of an NHL hockey game in Anaheim, Calif., Sunday, Feb. 23, 2020. (AP PhotoChris Carlson)

Vegas Golden Knights center Patrick Brown (38) scores past Anaheim Ducks goaltender John Gibson during the first period of an NHL hockey game in Anaheim, Calif., Sunday, Feb. 23, 2020. (AP PhotoChris Carlson)

Henrique brought the Ducks within a goal with 2:57 remaining when he knocked in a rebound after Nick Ritchie was stopped by Vegas' Malcolm Subban, then sent it to overtime with 1:15 remaining when the Ducks crashed the net.

Ritchie scored twice, including at tying goal 21 seconds into the third period, before Karlsson put Vegas ahead 4-3 6:28 into the third. He completed his hat trick at 11:05 with a backhand past goalie John Gibson's glove after getting a pass from Reilly Smith in front of the net.

Alec Martinez — who was acquired from Los Angeles on Tuesday — had a goal and an assist for Vegas, and Max Pacioretty added two assists.

Anaheim Ducks goaltender John Gibson, right, blocks a shot by Vegas Golden Knights center Paul Stastny during the first period of an NHL hockey game in Anaheim, Calif., Sunday, Feb. 23, 2020. (AP PhotoChris Carlson)

Anaheim Ducks goaltender John Gibson, right, blocks a shot by Vegas Golden Knights center Paul Stastny during the first period of an NHL hockey game in Anaheim, Calif., Sunday, Feb. 23, 2020. (AP PhotoChris Carlson)

Patrick Brown also scored and Subban made 25 saves for the Pacific Division-leading Golden Knights.

Ritchie and Henrique each also had two assists. Devin Shore also scored for the Ducks, and Gibson stopped 22 shots.

Brown opened the scoring when knocked in a rebound at 12:49 of the first period after Ryan Reaves circled the net and dumped it into the crease. Gibson stopped Gage Quinney's attempt with his right blocker before Brown put it in for his first goal of the season and second of his career. Brown was called up on Sunday after Nicolas Roy was injured during Saturday's win over Florida.

Vegas Golden Knights center Patrick Brown, left, checks Anaheim Ducks defenseman Jacob Larsson during the first period of an NHL hockey game in Anaheim, Calif., Sunday, Feb. 23, 2020. (AP PhotoChris Carlson)

Vegas Golden Knights center Patrick Brown, left, checks Anaheim Ducks defenseman Jacob Larsson during the first period of an NHL hockey game in Anaheim, Calif., Sunday, Feb. 23, 2020. (AP PhotoChris Carlson)

The Ducks evened it with 1.3 seconds remaining in the first when Shore was in the high slot and redirected Brendan Guhle's slap shot. Half of Shore's four goals this season have come against Vegas.

Ritchie gave the Ducks the lead midway through the second when he took advantage of a turnover near the Knights' net and knocked in a wrist shot after Nick Holden was unable to clear it. Martinez tied it at 2 five minutes later with a one-timer during an odd-man rush for his second goal since being traded by Los Angeles to the Golden Knights on Tuesday.

Karlsson briefly restored Vegas' lead to 3-2 19:03 into the second period.

Vegas Golden Knights center Patrick Brown, right, celebrates with defenseman Nick Holden, left, after scoring during the first period of an NHL hockey game against the Anaheim Ducks in Anaheim, Calif., Sunday, Feb. 23, 2020. (AP PhotoChris Carlson)

Vegas Golden Knights center Patrick Brown, right, celebrates with defenseman Nick Holden, left, after scoring during the first period of an NHL hockey game against the Anaheim Ducks in Anaheim, Calif., Sunday, Feb. 23, 2020. (AP PhotoChris Carlson)

NOTES: All of Karlsson's hat tricks have come with Vegas. The other two occurred during the 2017-18 season. ... Anaheim C Derek Grant, who could be dealt before Monday's trade deadline, was a healthy scratch.

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Golden Knights: Begin a four-game homestand against the Edmonton Oilers on Wednesday.

Anaheim Ducks center Devin Shore celebrates after scoring against the Vegas Golden Knights during the first period of an NHL hockey game in Anaheim, Calif., Sunday, Feb. 23, 2020. (AP PhotoChris Carlson)

Anaheim Ducks center Devin Shore celebrates after scoring against the Vegas Golden Knights during the first period of an NHL hockey game in Anaheim, Calif., Sunday, Feb. 23, 2020. (AP PhotoChris Carlson)

Ducks: Host the Edmonton Oilers on Tuesday.

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Vegas Golden Knights center William Karlsson (71) celebrates after his hat trick against the Anaheim Ducks during the third period of an NHL hockey game in Anaheim, Calif., Sunday, Feb. 23, 2020. (AP PhotoChris Carlson)

Vegas Golden Knights center William Karlsson (71) celebrates after his hat trick against the Anaheim Ducks during the third period of an NHL hockey game in Anaheim, Calif., Sunday, Feb. 23, 2020. (AP PhotoChris Carlson)
Anaheim Ducks goaltender John Gibson reacts after giving up the game winning goal to Vegas Golden Knights defenseman Shea Theodore during overtime in an NHL hockey game in Anaheim, Calif., Sunday, Feb. 23, 2020.The Golden Knights won 6-5. (AP PhotoChris Carlson)

Anaheim Ducks goaltender John Gibson reacts after giving up the game winning goal to Vegas Golden Knights defenseman Shea Theodore during overtime in an NHL hockey game in Anaheim, Calif., Sunday, Feb. 23, 2020.The Golden Knights won 6-5. (AP PhotoChris Carlson)

 Vegas Golden Knights defenseman Shea Theodore, right, scores the game winning goal past Anaheim Ducks goaltender John Gibson during overtime in an NHL hockey game in Anaheim, Calif., Sunday, Feb. 23, 2020.The Golden Knights won 6-5. (AP PhotoChris Carlson)

Vegas Golden Knights defenseman Shea Theodore, right, scores the game winning goal past Anaheim Ducks goaltender John Gibson during overtime in an NHL hockey game in Anaheim, Calif., Sunday, Feb. 23, 2020.The Golden Knights won 6-5. (AP PhotoChris Carlson)