London - Anthony Joshua cruised to a seventh round victory over Dominic Breazeale in a first world title defence on Saturday night.
The 26-year-old Briton floored his American challenger twice in the seventh round as he retained his International Boxing Federation (IBF) heavyweight title and extended his remarkable run of knockouts at the O2 Arena in London.
Joshua, who has stopped all 17 professional opponents since winning an Olympic gold medal at London 2012, inflicted Breazeale's first professional defeat in his 18th bout after controlling the fight from start to finish.
After setting a steady pace, Joshua exploded into action in the seventh round and Breazeale could not resist two vicious combinations.
Joshua is expected to make a mandatory defence against New Zealand's Joseph Parker by the end of the year or spring 2017.
Clashes against rival world champions, or fellow Briton David Haye, are likely to be next year at the earliest for Joshua, who increasingly is looking the man to beat in the heavyweight division.
Joshua's fellow Briton Tyson Fury will defend his World Boxing Association (WBA) and World Boxing Organisation (WBO) belts against former lineal champion Wladimir Klitschko later in the year now after spraining an ankle, while Deontay Wilder defends his World Boxing Council (WBC) title against fellow American Chris Arreola on July 16.
Breazeale arrived with an impressive 17-fight unbeaten record, with 15 wins by stoppage, and at 6ft 7ins (2.0 metres) was an inch taller than the champion.
But Breazeale could not halt the rapid momentum of Joshua's run in the professional ranks, which saw him win the IBF title with a two-round victory over American Charles Martin in April.
Former NFL quarterback Breazeale, from Los Angeles, lost his opening bout at the 2012 Olympics in London in the same weight category that Joshua won gold in.
It turned out to be another unsuccessful trip to London for Breazeale.
Joshua began positively and landed a decent three-punch combination late in the first, but Breazeale also slipped away from some of his jabs.
Breazeale, 30, was under more pressure at the start of the second when Joshua landed a flurry of power punches.
Joshua got back behind his jab and was working patiently until a combination left Breazeale staggering back on spaghetti legs.
Breazeale survived that crisis but in the third round his right eye was almost swollen shut but he bravely battled on to become just the second professional opponent to take Joshua past three rounds.
Joshua was content to take his time by boxing at a steady pace, wobbling Breazeale with a right in the sixth when the American gamely returned fire and bloodied the Briton's nose.
It was all over in the seventh when Breazeale was floored twice by combinations. He bravely got up after being decked by a left and a right but after a blizzard of blows was returned to the canvas and the fight waved off.
George Groves won a WBA super-middleweight title eliminator against fellow Briton Martin Murray on the undercard. Groves, a loser in three world title fights, earned scores of 118-110 on all three scorecards after wobbling Murray in rounds eight, nine and 12.