MANCHESTER, England (AP) — Carl Froch recovered from a first-round knockdown to retain his WBA and IBF super-middleweight titles with a ninth-round stoppage of George Groves in an engrossing all-British fight on Saturday.

Referee Howard Foster infuriated Groves and a packed crowd of 21,000 spectators at Manchester Arena by intervening to end the fight after Froch finally landed some meaningful punches to leave the challenger wobbling for the first time.

"I feel that the ref got it wrong," Groves said. "There's no way it should have been stopped. It's a bitter pill to swallow."

Groves, who sunk to his first loss in 20 fights, protested that he was OK almost immediately after Foster declared the fight over, and skulked around the ring shaking his head and mouthing: "That's rubbish."

He did appear to drop his hands as Froch unleashed a barrage of blows and then stumbled into Foster, perhaps explaining the referee's decision.

"What do you want to see," Froch asked, "a kid unconscious on the floor and carried off on a stretcher? At 25, that could have been a career-ender for him."

Groves was the big underdog but after a confident, commanding performance that often exposed the 36-year-old Froch, he was roundly cheered by the crowd who wanted to see more of a fight that was developing into a British classic. Members of the two corner teams squared off soon after the fight ended as emotions threatened to boil over.

"I think I'm a victim of my 'chinny' reputation and a victim of Froch's supposed punch power," said Groves of his supposed glass before demanding a rematch.

Froch registered his 32nd win in 34 fights but he will count himself lucky to have come through a gripping encounter with his belts intact. He was never comfortable as Groves commanded the center of the ring from the start — as he said he would — and unsettled the champion with his speed and movement.

Relations between the fighters had grown increasingly bitter in the build-up, with Froch losing his usual cool demeanor and becoming riled by what he perceived as a lack of respect shown by a young upstart. As it turned out, it was Froch who showed Groves disrespect, underestimating an opponent that looks to be a champion in the making.

A pro-Froch crowd even turned against their man as he celebrated his win.

"I'm devastated that I got booed out there in the arena," said Froch, his face swollen and covered in bruises.

This was Froch's 11th straight world title contest and he has fought a number of the sport's top boxers in Andre Ward, Mikkel Kessler and Jermain Taylor since 2008. Many were saying this was a fight Froch didn't need, with his reputation on the line against a hungry boxer whose awkward style was always likely to cause problems.

All that experience counted for nothing early on, as Groves took the center of the ring and sent Froch to the canvas with a right jab. The bell saved a wobbling Froch just as Groves went in to finish him off.

Groves wasn't overawed in the biggest fight of his life, leaving Froch unsteady on his feet with a raft of punches in the second round and then rocking him back with a straightener in the third.

Groves' right eye started to close over by the fourth round but he was still bossing the fight, shuddering Froch back with a right. The champion then walked into a left hook in the next and Groves was winning the close exchanges.

A frustrated Froch was warned twice by the referee and looked out on his feet by the time he returned to the corner after the eighth round.

However, he connected with a slew of big punches in the ninth, finally wobbling Groves, and the referee thought the challenger had taken too much.

"We are going to look back at it and see if anything can be done," Groves said. "This won't sit easy with me."