Amir Khan is back. The former IBF junior welterweight champion made his presence known quickly when he scored a first-round knockout of Phil Lo Greco on Saturday night in Liverpool, England.

Khan (32-4) scored his first knockout win since 2011 when he stopped Zab Judah in the fifth round. It was the fastest knockout (40 seconds) of his professional career and first first-round KO since 2008. 

Khan dropped Lo Greco (28-4) with a heavy overhand right to start the action that left Lo Greco dazed, but still able to stay on his feet. Khan then stunned Lo Greco again with a three-punch combination that tossed the Canadian into the ring ropes before Khan came in with the finisher before the referee stepped in to stop the action. 

After the fight, Khan quickly turned his attention to Kell Brook, who is looking for another big fight after suffering consecutive losses to Gennady Golovkin and Errol Spence Jr. in the last two years.

"The weight is an issue with Kell, I'm a 147-pound fighter," Khan said after the win. "I will fight and beat Kell Brook and the world knows it. Brook's been living off my name for a long time. I came and signed with Matchroom, I'm the one chasing Kell."

It was an impressive performance from Khan, to say the least, in his first action since being knocked out cold by Canelo Alvarez in 2016.