Amir Khan (left) and Marco Antonio Barrera both made weight Friday for their fight Saturday in Manchester, England. Photo / frankwarren.tv

This is what the Amir Khan-Marco Antonio Barrera fight on Saturday in Manchester, England boils down to: Is Khan any good and does Barrera have anything left?

Those questions are what make the fight intriguing enough to watch on pay per view (1 p.m. PT, 4 p.m. ET).

Khan, a silver medalist in the 2004 Olympics, was one of the hottest prospects in the world. Tall, quick, powerful, well-schooled, he seemed to have it all. Then he got whacked out in one round by unknown Breidis Prescott last September and everything changed.

Now, Khan (19-1, 15 knockouts) must prove that he’s more than hype. He stopped journeyman Oisin Fagan in his subsequent fight – and first with Freddie Roach as his trainer – but now faces a much bigger test, assuming Barrera isn’t shot.

The choice of Barrera was a curious one. Khan could’ve built toward a title shot against a lesser opponent. However, the benefit might be worth the risk: If he beats a fighter of Barrera’s ilk, then he takes a giant step back toward respectability.

“Yeah, you know, it's been a tough few weeks,” Khan said last week. “The biggest fight of my career at the moment. I've taken it with both hands, I've not given up. Still working hard, watching videos and preparing for the fight, staying focused.

“And I can't wait for Saturday, it's going to shut a lot of people up, it's going to shut all the critics up and it's going to bring out the best of Amir Khan.”

He and his handlers are confident that his advantages in height (four inches taller than Barrera), natural size (Barrera is facing a good fighter at 135 pounds for the first time) and quickness will be too much for Barrera to overcome.

As television analyst Larry Merchant pointed out, declining fighters are often able to compete with slower opponents who come at them but have trouble with young, quick fighters like Khan.

However, all eyes will be on Khan’s chin after the Prescott debacle. Barrera (65-6, 43 KOs) has never been a huge puncher but he can hurt an opponent with one shot and certainly can do damage with combinations, as his knockout ratio indicates.

Khan doesn’t seem to be worried.

“Making that little mistake in the Prescott fight made me realise I can't be rushing in there,” Khan said. “I've got away with it in earlier fights, but now I'm moving into world class level. You have to think, you have to be fit, you have to pace yourself and you have to think about every move you make.

“And I know I've got a great style and I've got good techniques and I should use them. Instead of using my heart, use my brain a bit more.”

What if he’s wrong?

“It depends on how he loses it,” Merchant said. “If it turns out to be hell of a fight and he conducts self in a positive way but happens to lose, he may gain ground. If he goes out there and just gets out-slicked and beaten up by Barrera, then it’ll be a long road back to convince people he is going to be a serious fighter.”

Barrera, a seemingly old 35, would have at least as much to lose. If he doesn’t win on Saturday, his remarkable career might be over.

The last time he looked like the savage Barrera who captivated us all these years was against Juan Manuel Marquez almost exactly two years ago. He gave THE RING’s No. 2 fighter pound-for-pound hell but lost a close fight.

Four months later, in October of 2007, he fought pound-for-pound king Manny Pacquiao but was uncharacteristically cautious and lost a one-sided decision. He’s fought two no-name opponents since, which tells us nothing.

So which Barrera will show up? The faded one or the Barrera of old? Remember, he has been counted out several times before but returned to glory.

And he has experience spoiling the plans of young British fighters. Barrera, thought to be declining, embarrassed then-unbeaten Naseem Hamed to win a clear decision in 2001 and resurrect his career.

“That’s good that they say I’m not a (legitimate) contender,” Barrera said. “I’ll have more to prove in the fight. I know who I am. ÔǪ Freddie Roach thinks that because he has one great fighter (Pacquiao) all his fighters are great.

“I just want to make it clear to him: Marco Antonio Barrera will be 100 percent. He better get that kid ready.”

Barrera almost had to cancel or postpone this fight because of a cut over his left eye, the result of a head butt against last-minute replacement Freudis Rojas in an ill-advised fight in January in Mexico.

However, he saw this as an opportunity he couldn’t pass up because he believes it will propel him back into the big-money title picture in and around the deep lightweight division.

Retirement, it seems, is the last thing on his mind.

“I know I can retire and be a legend right now,” he said. “I’m only 35, though. I still have a lot to give to boxing. Retirement will come one day. For now, March 14 is what I’m looking forward to. Beating someone in his own town will be a double victory for me.

“ÔǪ I’ll win this fight, have a couple more fights, and then we’ll see.”

Yes, we’ll see.

Michael Rosenthal can be reached at [email protected]