Conor McGregor stopped Donald Cerrone with a head kick and punches 40 seconds into the first round at UFC 246 on Saturday night, announcing his return to mixed martial arts with his first victory since 2016.

The Irish former two-division champion returned from a three-year stretch of inactivity and outside-the-cage troubles with a performance that echoed his greatest fights during his unparalleled rise.

McGregor (22-4) floored Cerrone (36-14) only 20 seconds into the bout with a perfectly placed kick, and he mercilessly finished on the ground to the delight of a sellout crowd at T-Mobile Arena.

Holly Holm kicks Raquel Pennington during a UFC 246 women's bantamweight mixed martial arts bout Saturday, Jan. 18, 2020, in Las Vegas. (AP PhotoJohn Locher)

Holly Holm kicks Raquel Pennington during a UFC 246 women's bantamweight mixed martial arts bout Saturday, Jan. 18, 2020, in Las Vegas. (AP PhotoJohn Locher)

McGregor’s hand hadn’t been raised in victory since November 2016, when he stopped lightweight Eddie Alvarez to become the first fighter in UFC history to hold two championship belts simultaneously. With his fame and fortune multiplying, McGregor fought only his boxing match with Floyd Mayweather in 2017, and he lost a one-sided UFC bout to lightweight champion Khabib Nurmagomedov in late 2018.

After a year of inactivity and trouble outside the cage, McGregor vowed to return to elite form in this bout against a fellow UFC veteran and stoppage specialist. His dramatic victory over Cerrone indicated he's on his way.

Cerrone is the winningest fighter in UFC history with 23 victories inside the octagon, a mark that reflects both his durability and commitment to an uncommonly busy schedule. Cerrone, who also holds the UFC record with 16 stoppage wins, had fought a whopping 11 times since McGregor's win over Alvarez, and he was in the cage for the 15th time since he lost his only UFC title shot in December 2015.

Conor McGregor smiles after defeating Donald "Cowboy" Cerrone during a UFC 246 welterweight mixed martial arts bout Saturday, Jan. 18, 2020, in Las Vegas. (AP PhotoJohn Locher)

Conor McGregor smiles after defeating Donald "Cowboy" Cerrone during a UFC 246 welterweight mixed martial arts bout Saturday, Jan. 18, 2020, in Las Vegas. (AP PhotoJohn Locher)

But Cerrone’s last two fights were stopped when he took too much damage, and he couldn't block McGregor's decisive kick or recover from the punishment on the ground.

McGregor believes he can recapture the fearsome form he showed during his meteoric rise to unprecedented MMA success. He won 15 consecutive fights during a five-year run from low-profile shows in Dublin to the world’s biggest MMA events, stopping five straight elite UFC opponents with punches on the way up.

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