Oakland, California - Andre Ward stopped Chad Dawson in the 10th round on Saturday to remain unbeaten and retain his World Boxing Association and World Boxing Council super middleweight world titles.

Ward pummelled Dawson - the reigning WBC light heavyweight champion who came down in weight to take the fight - sending him to the canvas in the third and fourth rounds before his final barrage ended it at 2:45 of the 10th.

Dawson rose from the canvas but looked dazed before referee Steve Smoger called a halt.

"These kinds of fights, you've got to take risks... you can mess around and lose your title to a fighter of that calibre," said Ward, who improved to 26-0 with 14 knockouts.

Dawson fell to 31-2 with 17 wins inside the distance.

Ward's speed and punishing left hand neutralised Dawson's height and reach advantage. It was a left to the chin that sent
Dawson down for the first time late in the third round.

Early in the fourth Dawson was down again as Ward landed another solid left and Ward was on top throughout the round with blows to Dawson's body and head.

It was an impressive performance from the super middleweight champion who is respected for his skills but had not posted a win inside the distance since 2009.

"I love to win," said Ward, who won Olympic gold for the United States at Athens in 2004 and emerged last year on top of the Super Six tournament to unify the super middleweight titles. "Finishing guys is the last piece of the puzzle."

Dawson not only came down in weight, he agreed to fight in Ward's hometown of Oakland. He praised Ward, but hinted that dropping the weight may have been more draining than he realised.

"He's a lot faster than I thought," Dawson said. "I wanted to fight the best and he's the best. I thought I felt good at 168 (pounds, 76 kilograms), but I couldn't get off.

"I don't want to take anything away from Andre Ward," added Dawson, who said he would return to the higher weight class and move on.

On the undercard, WBC lightweight champion Antonio DeMarco of Mexico stopped John Molina Jnr 44 seconds into the first round.

DeMarco improved to 28-2-1 with 21 knockouts while Molina fell to 24-2.