Boxing/ WBC light-middleweight title fight: In the end the action did not quite match the hype. Always absorbing but never a classic, the fight touted as the biggest money-spinner in history produced a new WBC super-middleweight champion in Floyd Mayweather Jr after he scored a split-decision victory over Oscar De La Hoya to maintain his undefeated professional record and add weight to his claim to be ranked as the best pound-for-pound fighter in the sport.

The sell-out crowd of 16,700 at the MGM Grand, Las Vegas, had roared its overwhelming support for De La Hoya, among the most popular and marketable figures that boxing has produced in the past 20 years. But his pride and aggression could not subdue Mayweather's slippery skills. At times the new champion can be obnoxious but on Saturday night he proved beyond doubt he is an outstanding boxer, if not quite the legendary figure he believes himself to be.

In his first fight in more than 2½ years De La Hoya may have surprised Mayweather with his hand speed, particularly in the early rounds, but Mayweather finished the stronger, at least according to two of the judges, Jerry Roth and Chuck Giampa, who scored the fight to the challenger, winning four of the last five rounds on their cards. Mayweather prevailed by scores of 115-113 and 116-112, with the third judge, Tom Kaczmarek, scoring the contest to De La Hoya 115-113.

The crowd loudly jeered the outcome. For all his silky movement and crisp punching, Mayweather inspires only grudging admiration. He is a defensive boxer and many of those who produced record Las Vegas gate receipts of more than $19 million believed De La Hoya's greater aggression should have carried the day.

De La Hoya had worked out smart tactics with his new coach, Freddie Roach. He would not expend unnecessary energy chasing shadows. Instead he would aim to cut off the ring, keep a tight, almost peek-a-boo defence and then throw eye-catching volleys of punches. For a while he was bossing the fight, but Mayweather grew in confidence when he landed a terrific right hook in the fifth which appeared to stun the champion.

Perhaps the years took their toll on De La Hoya - at 34, he is four years Mayweather's senior - or maybe it was the challenger took time to work out a way to cope with his strategy. The conclusion might have been made that De La Hoya is not quite the fighter he once was. As for Mayweather, for all his speed and awkwardness he is no Sugar Ray Leonard. Any acknowledgement of greatness would demand more than he showed here.

If he is true to his word, Mayweather will walk away from the ring, undefeated in 38 contests and a world champion in a fifth weight division. "He threw a lot of punches but they weren't landing," he said. "I could see the shots coming . . . He's the best fighter of his era and I beat him. Now I'm going to retire. I don't have anything left to prove. I have made a ton of money from the sport and I want to spend more time with my children."

Inevitably there will be talk of a rematch. But De La Hoya said he would take time to review his performance before making a statement about his intentions. He does not need the money. But he was sounding like a man who believed he had been wronged.

"If I didn't press the fight, there would be no fight," he said. "I hurt him with a few punches. I was pressing and I wanted to stop him. I was trying to close the show. I am the champion and you've got to do more than that to beat the champion. I believe I won the fight."

• Guardian Service