Defending champion Andy Murray was the latest Grand Slam winner to be bundled out of the US Open and deny fans a dream matchup, while Novak Djokovic stayed the course on Thursday to complete the last four lineup.
Winds blew across Arthur Ashe Stadium but that did not bother top seed Djokovic, who defeated Mikhail Youzhny of Russia 6-3, 6-2, 3-6, 6-0 to claim a berth in Saturday's semifinals.
An eagerly anticipated renewal of his grand slam rivalry with Wimbledon winner Murray had already been spoiled after ninth seed Wawrinka of Switzerland spanked the out-of-sorts Scot 6-4, 6-3, 6-2 in their quarterfinal.
The other semifinal will have French Open champion Rafael Nadal against eighth-seeded Frenchman Richard Gasquet.
"I'm always trying to play my best tennis in the Grand Slams," said world number one Djokovic, who reached his 14th consecutive Grand Slam semifinal. "I'm really working on my game."
Youzhny, the 21st seed, said the Serb had never given an inch. "Every point you have to play," the Russian said. "He never miss. He never give you some presents."
Wawrinka stepped out from the shadow cast by compatriot Roger Federer and into his first Grand Slam semifinal with a decisive victory over the Wimbledon champion, winning the battle from the baseline and the net.
The surging Wawrinka, who raised his 2013 record to 41-15 with the upset win, raised both arms in triumph after third seed Murray dumped a second-serve return into the net on match point.
"It feels amazing for sure, especially here," the excited Swiss said. "He's defending champion, he's a tough opponent. It was a crazy match for me. To beat him in three sets is just amazing."
Wawrinka broke the Briton four times and never faced a break point against a player noted for his ability to return. He cracked 45 winners past the listless Murray and won 31 of 42 forays to the net in the one-sided match.
Murray admitted to a Wimbledon hangover after ending a drought of 77 years without a British winner since Fred Perry's 1936 triumph at the All England Club.
"When you work hard for something for a lot of years, it's going to take a bit of time to really fire yourself up and get yourself training 110 percent," he said.
"That's something that I think is kind of natural after what happened at Wimbledon," added Murray, who beat Djokovic in the Wimbledon final and to win the 2012 US Open title while losing the Australia Open final to the Serb in between.
Much more was expected of Murray, as it was for the other Swiss player that factored at Flushing Meadows -- Federer.
Murray's loss was the second seismic shocker to strike the men's draw in the last two rounds following the straight sets dismissal of five-time US Open champion Federer in the fourth round by Spain's Tommy Robredo.
Robredo's rousing victory robbed fans of a quarterfinals match between Federer and Nadal that would have marked the first US Open meeting between the two, who have met 31 times elsewhere around the world.
Djokovic, one week younger than his friend and fellow 26-year-old Murray, would seem to benefit from the shuffle.
The Serb has a narrow 11-8 career mark against Murray, having won their first four meetings at the start of their pro careers, but is 12-2 including the last 11 against Wawrinka.
Murray complained about the breezy conditions, but gave credit to Wawrinka.
Friday's women's semifinals will feature defending champion Serena Williams of the United States against Li Na of China, and 2012 runner-up Victoria Azarenka of Belarus against unseeded Italian Flavia Pennetta.
The Day 12 program begins with the mixed doubles final pitting Czech Andrea Hlvackova and Belarus veteran Max Mirnyi, against American Abigail Spears and Mexican Santiago Gonzalez.
Sania-Zheng exit
Sania Mirza’s campaign ended with a tame semifinal defeat in the women’s doubles with partner Jie Zheng against Ashleigh Barty and Casey Dellacqua.
The 10th-seeded Indo-Chinese pair lost 2-6, 2-6 in an hour and five minutes to the Australian eight seeds.
Results (quartefinals, prefix denotes seeding): Men’s singles: 1-Novak Djokovic (Srb) bt 21-Mikhail Youzhny (Rus) 6-3, 6-2, 3-6, 6-0; 9-Stanislas Wawrinka (Sui) bt 3-Andy Murray (Gbr) 6-4, 6-3, 6-2.
