Kyle Edmund was beaten by Marin Cilic in straight sets, winning 6-2 7-6 (7-4) 6-2 to reach his first Melbourne final, where he will face Roger Federer or Hyeon Chung.
Victory would have seen him leapfrog Andy Murray as British number one, as the Scot is expected return from hip surgery for the grass-court season in June.
Edmund had been trying to become the fourth British man to reach a grand slam final, but Cilic appeared to be too powerful for the Brit.
Cilic, the 2014 US Open champion, dominated from the outset, while Edmund required a medical timeout after the first set and appeared to be bothering the Brit in the closing stages.
The Croat was playing in his fifth major semi-final, and trying to reach a third Grand Slam final, while Edmund has yet to make it past the semi-finals of any ATP tournament.
His tournament began with what was then a career-best win over 11th seed Kevin Anderson and included a stunning victory against third seed Grigor Dimitrov.
The Yorkshireman’s game has improved massively in the new season but the gulf in experience ultimately showed in an dominant performance from Cilic.
Edmund is scheduled to head straight to Marbella for Great Britain’s Davis Cup tie against Spain, which begins next Friday.
