The 30-year-old Serb, who has prevailed in some of the sport's epic battles on the way to 12 major titles, was barely recognisable as he capitulated in a 7-6 (5) 6-3 6-0 defeat by Austrian Dominic Thiem in the quarter-finals.
Wawrinka made it eight straight wins over Cilic with a 6-3 6-3 6-1 demolition of that saw him rip through the match in under two hours - Wawrinka, like Nadal and Thiem has not dropped a set this tournament.
The defending champion from Serbia lost to sixth-seeded Dominic Thiem 7-6 (5), 6-3, 6-0 in the quarterfinals.
That helped Nadal to become the first player to enter the French Open semi-finals for the 10th time.
The fourth-seeded Nadal led 6-2, 2-0 when No. 20 seed Carreno Busta stopped after 51 minutes of play. Just a pretty bad set.
"Trust me, I'm thinking about many things", he said. "I have played good matches on the whole".
"But I am just trying to sense what is the best thing for me right now". "It's a big challenge but I am up for it".
Trump Cites London Attack To Make Gun Control Point
President Donald Trump greets British Prime Minister Theresa May in the White House Oval Office in Washington , U.S., January 27. He announced his intentions, if elected, to phone Trump and "ask him if he would kindly reconsider that".
"All and all, I think it was decided in the first set", Djokovic said after the match.
The two men's quarter-final matches due to be played at the French Open yesterday have been postponed until today after rain disrupted play at Roland Garros, organisers said. Thiem saved the first set point with a volley, then forced a backhand error on the second.
Chasing a 15th major overall, Nadal has conceded 22 games this tournament in reaching the semi-finals - the fewest in glorious French Open career and bettering the 25 he lost in 2006. Beyond all that, as I said at the start of the tournament, everything that is being said and written. of course you have a job to do, but my job is to play tennis.
The turning point against Nishikori - who upset Murray at last year's US Open - came when the latter won the third-set tiebreak without dropping a point.
After the defeat, Djokovic was accused of "tanking" by several analysts and commentators covering the 2017 French Open.
Pliskova reached the U.S. Open final a year ago, but the Czech player had never been past the second round at Roland Garros in five previous appearances.