Pavlik (l) and Martinez go toe-to-toe at Boardwalk Hall, Atlantic City
Sergio Martinez claimed Kelly Pavlik's WBO and WBC middleweight titles by a unanimous decision in Atlantic City.
Martinez, 35, was floored in the seventh round but opened a cut above American Pavlik's right eye in the ninth and dominated the final rounds.
"It was a 12-round plan," said Argentine Martinez, who got the verdict 116-111, 115-111 and 115-112.
"I knew in the long run he would show his true championship colours but I knew I had to finish off strongly."
Martinez (45-2-2 24 KOs) dazzled his 28-year-old opponent with his superior speed and footwork in the early rounds, scoring well with right jabs and straight lefts.
Pavlik (36-2, 32 KOs), though, grew into the fight in the middle rounds and when Martinez walked into a short right hand that sent him crashing to the canvas in the seventh the bout appeared to swinging in the American's favour.
Martinez earned a career-high $1m (£650,000) for the win
However, two rounds later the blood was streaming down Pavlik's face after Martinez had busted open a cut over his right eye.
"I couldn't see," said Pavlik. "It was like a white-out in my right eye. I could still see punches, but he fought a smart fight, doubling on the left hand.
"He'd throw a left, I'd block it, and he'd throw another one. He wasn't hurting me or nothing, but he was catching me with punches, and it looked bad. There's nothing you can do about that."
Pavlik weakened considerably and Martinez, sensing victory, landed quick punches in the closing stages to score heavily with the judges.
"It's a tremendous pride," said Martinez, who had stepped up to the 160lb division after being the WBC's light middleweight champion. "Incredible. I can't explain it at this moment."
Meanwhile, in Montreal, Romania's Lucian Bute retained his IBF super-middleweight belt with a third-round knockout win - his 26th straight victory - over Colombia's Edison Miranda.
And German Robert Stieglitz recorded a 12-round unanimous decision (119-108, 117-111 and 117-110) over compatriot Eduard Gutknecht to retain his WBO super-middleweight title on home soil in Sachsen-Anhalt.