There is so much on the line Saturday at Madison Square Garden when Amir Khan faces Terence Crawford in a world welterweight title bout.

Some consider Crawford to be the best pound-for-pound fighter in the game today. Others say Crawford has avoided the big fight and has beaten opponents he knew he could handle. But this bout changes that.

Khan, meanwhile, is known for his attacking style — but sometimes fragile chin. He’s an Olympic silver medalist (2004) and has never shied away from a big fight.

Tonight these fighters take to the ring. One tries to emerge officially as the world’s top pound-for-pound fighter, while the other looks to revitalize a potential Hall of Fame career.

USA TODAY Sports’ Martin Rogers will provide round-by-round analysis of the bout right here.

PREFIGHT

Crawford and Khan are making their final locker room preparations for what will be a hugely significant fight for both of them. Make no mistake, if Khan’s skills and footwork are at their silky best, this will be the toughest test of Crawford’s career.

And here they come, Khan looking relaxed yet focus ahead of a fight that could transform his career, Crawford with a look for stern intensity. If there is a finer boxing venue in the world than MSG, I’ve yet to see it. This should be good.

ROUND ONE

Khan looked solid in the early going, giving hint that his speed could prove to be a positive factor. Things looked evenly matched – until they weren’t. With 30 seconds remaining Crawford uncorked a straight right and had his opponent stood up, then felled him with a big left hook. Khan got to his feet but ate another big shot before the ball sounded. Massive start for the American, just what he was looking for. Round to Crawford obviously, who leads 10-8 on my card.

ROUND TWO

Decent recovery from Khan who at least has gotten himself into the fight. But Crawford looks immensely confident now and is comfortable with the Brit’s speed and movement. Crawford looks bigger and stronger which is a tough combination to combat. Crawford jabbing to fine effect and takes the round. He leads 20-17 on my card.

ROUND THREE

Crawford is in control at this point and hasn’t really been troubled. He is able to maintain good distance and is connecting with accurate, if not brutally powerful, strikes. Khan needs to change things up a bit here but no one has found an effective antidote to Crawford so far and this doesn’t appear to be the night when the champ’s streak ends. But things can change. For now, Crawford takes another round, and leads 30-26 on my card.

ROUND FOUR 

Highly active round and Khan is not going to give this one up without a fight. He got himself into the action, coming in from some different angles and giving Crawford something to think about. Khan got in some nice shots, highlighted by a crisp left hand that was the best punch of the round. Khan takes the frame on my card and trails 39-36 overall.

ROUND FIVE

Crawford made a strong start and moved back into the ascendancy. Khan kept on coming, and seemed to resume his straight-ahead approach, but even so managed to connect with a few late shots. This is a good and entertaining fight, but Crawford is in charge of it. Khan is asked by his corner if his right hand is hurt. Round to Crawford, who leads 49-45 on my card.

ROUND SIX

And now we have controversy. Crawford connects with a low blow 47 seconds into the round and the referee stops the action to allow Khan to recover. Except that he doesn’t recover. After only a minute or so, Khan’s trainer Virgil Hunter informs the referee that his fighter cannot continue. That means the result will go down as a technical knockout for Crawford, an unsatisfying end — but the contest was heading towards a victory for the American in any case.

AFTERMATH

The fans are not satisfied and it is a shame, because this still had a chance of becoming very interesting. Crawford says that Hunter stepped in to “stop his fighter from getting hurt” while Khan also seeks to clarify the situation. He says that his legs had gone after the low blow, that he felt sick to his stomach and could barely move. Crawford retains his WBO welterweight title and is now 13-0 in title fights.

— USA TODAY