Anthony Joshua made the first successful defence of his IBF heavyweight title by stopping Dominic Breazeale in seven rounds at London's 02 Arena.
The 26-year-old, who became a world champion at the same venue in April in his 16th fight as a professional, needed over three rounds for only the second time of his career to end his opponent's impressively-resilient challenge.
Another devastating left-right combination, similar to those that stopped many of his 16 previous opponents, so heavily sent Breazeale to the canvas it appeared the fight may be immediately over.
He returned to his feet, clinging to the last seconds of his undefeated professional record, before a further barrage heavily dropped the American and left referee Howard Foster with little choice but to wave the action over after one minute and one second.
Joshua had spoken in the fight's build-up of his desire to demonstrate the footwork and mobility he has been working on in training.
He also said, however, that he has yet to build the confidence not to finish an opponent when they are vulnerable, and so it again proved.
Joshua showed reasonable patience throughout the opening round, frequently landing left jabs and the occasional hurtful right, even showing a previously-unseen head movement to evade a Breazeale counter.
In the second he displayed greater aggression. He punched through the gun-shy American's high guard, and repeatedly sought - and often successfully found - Breazeale's resistant head with uppercuts, left hooks and straight rights. Significant swelling was already appearing around Breazeale's right eye.
What followed was a demonstration of Joshua's relish of combat. Breazeale's impressive punch resistance ensured he remained on his feet, and when he fought back and landed, Joshua responded with greater malice.
His inexperience showed at one point with punches that missed wildly, while the American continued to absorb heavy punishment in the rounds that followed, particularly a perfectly-timed left hook midway through the fifth.
The most impressive boxing performance of Joshua's career unfolded until the breakthrough came with that combination in the seventh. He clinically finished the American, reminding all of his exceptional power.
It is expected he will next face mandatory challenger Joseph Parker, of New Zealand.
George Groves impressively revived his career with one of his finest wins by earning a unanimous decision victory over fellow Englishman Martin Murray.
The three judges scored him a 118-110 winner as his superior speed and variety ensured he outboxed his game opponent, taking him closer to a fourth world title fight.
It also leaves Murray facing a significant challenge in rebuilding his reputation, let alone achieving his ambition of becoming a world champion.
Chris Eubank Jnr won his first fight since ending Nick Blackwell's career by stopping Tom Doran in four rounds.
Victory also represented the first defence of the British middleweight title he dramatically won from Blackwell in March.