Amir Khan admits he only has himself to blame after suffering a crushing fourth-round defeat to Danny Garcia in Las Vegas.
Khan was floored three times by the American fighter, meaning Garcia walked away with his WBC light-welterweight title and snatch his opponent's WBA belt.
Khan was taken to hospital for precautionary scans after the devastating loss, which was his second in succession after Lamont Peterson's tainted win over him last December.
Khan said: "It wasn't my night, after watching the replays a little bit I thought I was coming in with my hands down and Danny took advantage. I respect Danny, he was countering very well against me."
Khan, now 26-3 with 18 early wins and two stoppage defeats, hinted he may have taken Garcia lightly. His tactics backed that up as he tore at his opponent from the opening bell before becoming embroiled in a war which he lost spectacularly.
Khan, who had perhaps naively talked about fighting Floyd Mayweather in the near future, had the WBA belt he lost to Peterson returned to him this week but lost it again to Garcia at the Mandalay Bay Events Center.
Garcia, now 24-0, said: "I always knew I was going to win this fight and I'm now a unified champion at 140lbs.
"I needed a great fighter in front of me to show how good a fighter I am. Now everyone knows. I'm a killer. I will fight anyone, anywhere, anytime."