Amir Khan knew pretty early in his one-sided fight with Kell Brook on Saturday night that boxing probably isn’t for him anymore.

Khan trained hard with Terence Crawford’s team in the United States for their long-awaited domestic grudge match. The British star wanted nothing more than to knock Brook into the front row at AO Arena in Manchester, England.

The 35-year-old Khan became resigned as Brook battered him, though, that not only is he past his physical prime, but that he just doesn’t have that requisite fighting spirit within him anymore, either.

The former welterweight and junior welterweight champion confirmed as much during his post-fight interview with Sky Sports in his locker room.

“Forty fights,” Khan said. “I mean, a lot of fights, winning two world titles, fighting over there in America and around the world. I mean, I need to sit down with my family. But I think it is more towards end of my career now here. Obviously, that love of the sport is not there anymore, like it was before. When I was in the ring, obviously I used to have that, you know, that excitement and that push, but I just didn’t have it in me. I felt quite flat. And I think that’s maybe a sign for me to know that I should be calling it a day, maybe.

“But let’s see. I’m gonna go back, watch the video. Kell obviously came trained. He looked really, really good today, and he was ready. You know, and it’s very hard to beat a guy who just wants to win. I mean, I had a great training camp as well. But like I said, he just must’ve done that bit better than me. So, let’s see where we go from here.”

Sheffield’s Brook (40-3, 28 KOs) completely controlled his fight with Bolton’s Khan (34-6, 21 KOs), who was only a slight underdog according to oddsmakers prior to their scheduled 12-round, 149-pound bout. Khan never went down, but Brook beat him up to the point referee Victor Loughlin understandably stepped between them and halted the action 51 seconds into the sixth round.

“I’m very upset,” said Khan, who lost inside the distance for the fifth time in his 16-year pro career. “You know, I mean, I did all the training that we had to do in camp, over in Colorado [Springs] and then Omaha, Nebraska. Just couldn’t get it going, you know? Was falling a little bit short. I mean, look, no disrespect to Kell Brook. I think he put a great performance on. I mean, he did everything he needed to do in the fight, put on a great performance and obviously, he was the best man tonight.”

Khan hadn’t fought in 2½ years before Brook beat him. Brook, also 35, ended a long layoff as well, 15 months, though he was much fresher and sharper than Khan.

“I mean, I just couldn’t get going, really,” Khan said. “I mean, I was catching Kell with some good shots. Obviously, was falling a little bit short on a few things as well. I mean, look, it’s my own fault. I mean, look, I’m not blaming anyone. I had a great, great training camp with [Brian McIntyre] and Terence Crawford and everyone, but I just couldn’t get going, you know? Was falling short, obviously was missing quite a lot. But look, end of the day, Kell was on his ‘A’ game today. He boxed really well. A lot of respect goes out to him.

“And also, I wanna say a big thank you to all the fans that came out today. Ninety percent of them must’ve been there for me. I mean, when I heard my name, [the] cheering, it was amazing. So, I just wanna say a big thank you. And also, I wanna apologize to them for that, obviously, it didn’t go our way today.”

Keith Idec is a senior writer/columnist for BoxingScene.com. He can be reached on Twitter @Idecboxing.