Roger Federer has warned his rivals that he is at the peak of his powers after negotiating his way past American giant John Isner to move within one victory of the Olympic final.
The Wimbledon champion put on a clinical display to defeat 10th seed Isner 6-4 7-6 (7-5) and set up a semi-final meeting with Juan Martin del Potro, who defeated Japan's Kei Nishikori in straight sets.
The Swiss had to dig deep for his victory as swirling winds and powerful serves of over 200kmh from his opponent tested him greatly.
But the most decorated tennis player in history overcame the challenges with typical style to move within two victories of the Olympic singles gold that has eluded him throughout his career.
Just four weeks have passed since Federer equalled Pete Sampras's record of seven Wimbledon titles, and there is an inescapable sense that the 31-year-old is destined to claim Olympic gold here in Sunday's final.
"I think I am playing my best. I don't know if you can play any better," Federer said.
Defending champion Rafael Nadal, who missed the Olympics through injury, said before Wimbledon that the winner of the usual Championships at SW19 would also win the Olympics - and Federer does not disagree.
"I said the same," Federer said.
"We sometimes underestimate how important confidence is.
"When your confidence is high you don't ask many questions of yourself. I don't want to say that I feel invincible right now, but I feel good."
Federer's winning shot - a return that clipped the net cord and dribbled over - suggested that everything is going his way.
"I felt really bad, but I was relieved the game was over," said Federer, who crashed out of the men's doubles on Wednesday.
Novak Djokovic and Andy Murray will contest what looks like being another mouthwatering semi-final on Friday after their respective victories over Jo-Wilfried Tsonga and Nicolas Almagro On Thursday.
Djokovic played some sublime tennis on his way to sealing a 6-1 7-5 win on Centre Court.
Friday's's meeting will be the first time that the two have met on grass, and Murray is yet to beat the Serb in a grand slam.
Murray wasted little effort in dispatching Almagro to reach the last four.
Britain's No.1 fired down 15 aces to beat Almagro in just under an hour, although his task was helped slightly by the recurrence of a shoulder injury his opponent picked up earlier in the tournament.
The win was even more special for Murray as it came in front of the Duke and Duchess of Cambridge.
"It's always nice when you're playing in front of royalty," Murray said.
"Now I hope I can get a medal."