Rio de Janeiro - Andy Murray shrugged off a code violation for directing the word "stupid" at the umpire to crush Kei Nishikori 6-1, 6-4 and move one win away from becoming the first player to win back-to-back Olympic singles titles.
The world number two and reigning Wimbledon champion will face either 2008 Olympic winner Rafael Nadal or Juan Martin del Potro in Sunday's gold medal match.
Victory allowed 29-year-old Murray to extend his mastery over Nishikori to 7-1 and stretch his current winning streak to a career-best 17 matches.
But the Briton's routine win wasn't without incident.
He collected a code violation from match official Carlos Ramos who believed Murray had called him a "stupid umpire".
"I didn't say 'stupid umpire', I said 'stupid umpiring'. But if you want to be the star of the show, that's fine," argued Murray at a changeover.
Nishikori, 26, had to save three match points to beat Gael Monfils in the quarter-finals and the effort took its toll on Saturday when he was broken in the fourth and sixth games of the first set.
The Japanese star won just five points off the Murray serve in the opener and seven in the second when he was broken again in the sixth game.
He managed to save two match points but dumped the third into the net with a weary backhand and the contest was over in 80 minutes.
Later Saturday, Nadal tackles Argentina's del Potro, buoyed by his men's doubles gold with Marc Lopez on Friday night.
Nadal, a 14-time major winner, leads the head-to-head with the 2009 US Open champion by 8-4.
Del Potro, who knocked out world number one Novak Djokovic in the first round, won the pair's most recent match in Shanghai in 2013.
But since that time, the 1.98m (6ft 6ins) del Potro has seen his career stalled by a series of wrist injuries and a ranking slump to 141 in the world.
The 30-year-old Nadal has already played nine matches at the Olympics in his pursuit of double gold.
That's a gruelling comeback for a player who is in his first tournament in two and a half months after a left wrist injury forced a premature exit from the French Open.
"I'm in a disadvantage, obviously. If they do the order of play that way, scheduling me to play the second match (after the first men's singles semi-final) from 12:00, obviously I'm in an even bigger disadvantage," said Nadal.
"I don't understand the reason for that when I have only one match to play. I don't understand why they want to give me that disadvantage."