Wawrinka, who could play Murray in the semi-finals, had to have treatment to his lower back during his 7-5 7-6 (9-7) 6-2 win on Court One, which ended French hopes of a first male champion since 1983.
Should Murray improve on his 8-2 win record over Japan's Kei Nishikori in their scheduled quarter-final on Wednesday (7 June), only 2015 champion Stanislas Wawrinka or 2014 US Open victor Marin Cilic will stand between him and a place in the final.
Nishikori has won just two of 10 matches against Murray, but can't remember beating the British player at the U.S. Open previous year.
"Stan has played fantastic this tournament so far", said the Scot, who was beaten by Novak Djokovic in last year's showpiece.
This match is a toss-up in my eyes, as Wawrinka does have the edge on clay and is playing better tennis overall, but it's tough to bet against Murray and that defense.
"I played the best match here in Roland Garros against Carla, which always was a tough match", said Halep.More news: Beavers' streak at 23; Harrison slam fuels 13-1 win over LSU
Time violations are a contentious issue, with players allowed 25 seconds between serves in regular tour events but only 20 seconds at Grand Slams.
He is the oldest man to make the last four since Jimmy Connors in 1985.
"Today was a flawless match for me, I thought I played very well from the beginning", Wawrinka told a news conference.
The world No. 1 and top seeded Murray takes on the eighth seeded Nishikori on Saturday at the 2017 French Open.
- Second seed Karolina Pliskova came back from a set down to claim a 2-6 6-3 6-4 win over Paraguayan Veronica Cepede Royg.
"I think he's been great. We don't know what's going to happen on Friday, don't know how either of us are going to play, but with the right attitude, right game plan, right tactics, you can still win matches".More news: 8 things to know about Monday's severe storms and flash flooding
Djokovic put up little resistance in the one-way final set, winning a mere eight points as Thiem clinched victory with a backhand passing shot. He's great player. Very smart tennis player.
"Everyone knows who remains in the draw", said Svitolina, who was two points from losing before coming back to beat 290th-ranked Petra Martic 4-6, 6-3, 7-5.
None of the women left at the French Open have won a Grand Slam title, while Garcia and Svitolina have never before reached the semifinals of a major. Corretja worked with Murray between 2009 and 2011 centrally on his clay court game and believes his former protégé has timed his run of form perfectly.
The world No. 6 lost the opening set 6-4, before taking on a 6-3 victory to force a decisive set.
The fourth-seeded Nadal, a nine-time champion at Roland Garros, was leading 6-2, 2-0 when Carreno Busta stopped.
Remarkably, Nishikori was unable to recall the match at all when asked about it despite the win being one of the biggest of his career.More news: Puerto Rico's Vote for Statehood Means Nothing
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