Carson, CA -- (Sports Network) - Oscar De La Hoya, fighting for the first time in a year, dissected former sparring partner Steve Forbes in a lopsided 12- round unanimous decision victory at Home Depot Center.

It was the first fight of De La Hoya's three-bout farewell tour.

The 35-year-old De La Hoya (39-5) took apart Forbes (33-6) with textbook precision en route to taking the fight 120-108, 119-109 and 119-109 on the judges' scorecards in the junior middleweight bout.

The win sets up a likely rematch for "The Golden Boy" with undefeated WBC welterweight champion "Pretty Boy" Floyd Mayweather Jr. on September 20 in Las Vegas. Mayweather won a split decision over the 1992 Olympic gold medalist in De La Hoya's most recent fight, a title match in May 2007.

The bout with Mayweather will likely be the penultimate fight in De La Hoya's storied career, which has lost momentum in recent years with a 3-3 record in his last six fights.

Forbes, who has never been knocked down in his 11-year career, has now lost three times in his last four fights.

De La Hoya held a three-inch height advantage over Forbes and used it to his advantage throughout the fight, peppering Forbes with an accurate jab that opened him up for several different combinations in the opening rounds.

Forbes, four years De La Hoya's junior, fought conservatively in the early going but opened up in the middle rounds, swinging wildly with uppercuts and dancing around De La Hoya on multiple occasions.

But, De La Hoya's jab continued to find the mark throughout the fight, and the Los Angeles native asserted his control by opening up a cut next to Forbes' right eye midway through round six, then wobbling Forbes with a straight right hand in the final seconds of the round.

De La Hoya began mixing in an uppercut in the seventh round, and while Forbes would often try to steal rounds with a late burst, the former world champion in six divisions was never in serious trouble and staggered Forbes with a pair of seventh-round combinations. While De La Hoya did not succeed in being the first fighter to take Forbes off his feet in 39 professional fights, the decision victory was never in doubt.

In a twist, both fighters were trained by members of Mayweather's immediate family. De La Hoya trained under his father, Floyd Sr., while Forbes was conditioned by his uncle, Jeff Mayweather.