After losing to Juan Manuel Marquez last year, Juan Diaz changed his style in hopes of reversing the outcome in last nights rematch at Mandalay Bay Casino in Las Vegas, NV but despite boxing smarter, Diaz was again handed defeat in a battle for the WBA and WBO lightweight titles.
Diaz largely abandoned his aggressive volume punching methods to try his hand at outboxing his Mexican rival but Marquez proved able to adapt to the stylistic departure.
Marquez showed no ill effects from his loss almost a year ago to Floyd Mayweather at welterweight and was not bothered by ring rust nor having to make the 135 pound limit.
Diaz had his best moments in the early rounds as Marquez took awhile to adapt to his foe's change of tactics but by the middle frames Marquez had found his bearings.
The Mexico City native was able use his superb countering skills to negate Diaz's attempts to jab his way in and the Houston man was never able to establish a consistent offense.
Marquez was the more accurate puncher but Diaz had his moments in the contest, as the champion's swollen right eye aptly displayed by the later rounds.
The contest ran its course after a slugfest of a 12th and Marquez retained the WBA and WBO lightweight titles via scores of 118-110, 117-111 and 116-112.
Marquez's record now stands at 51-5-1 (37), while Diaz has lost four of his last six to drop to 35-4 (17).
The vacant WBO middleweight title was at stake on the undercard in a clash between undefeated, highly touted prospects Daniel Jacobs and Dmitry Pirog.
Jacobs was favored going into the fight but the American had a difficulty dealing with the movement and angles of his Russian counterpart, who won the first two frames.
Jacobs bounced back in the third and fourth, getting on his toes and catching the oncoming Pirog with some good shots but the visitor was making Jacobs expend a lot of energy.
Shortly after the fifth started, Pirog beat Jacobs to the punch when both were throwing right hands and Jacobs hit the canvas hard, prompting referee Robert Byrd to wave off the contest at 0:57 of the round.
Pirog goes to 17-0 (14), while capturing the vacant WBO title as Jacobs, 20-1 (17), loses for the first time.