"I think I played one of my best matches on clay", Halep told reporters after Thursday's win.
American duo Sloane Stephens and Madison Keys will square off in the Roland Garros semi-finals on Thursday, in a rematch of last September's US Open final. She had her second shot at the title in 2017 but lost again to the Latvian revelation Jelena Ostapenko.
"I am very pleased to be in another final in Paris", said Muguruza who has yet to drop a set in the tournament and claimed her first win over Sharapova in 4 meetings. So long ago has it been that he was the semifinal opponent for Roger Federer's only French Open title, when Federer had to win the fourth and fifth sets to surpass del Potro.
Romania's Simona Halep celebrates after victory over Germany's Andrea Petkovic at the end of their women's singles third round match on day seven of The Roland Garros 2018 French Open tennis tournament in Paris on 2 June 2018.
But it took Muguruza quite a while to get going against Halep, who managed to keep sending ball after ball back over the net.
"I have recognised more things I have needed to do".
Wimbledon champion Muguruza, considered the slight favourite by many, handed her serve over in the first game with a double fault on break point and Halep raced 5-0 ahead in the opening set. "I've had issues with the right pectoral muscle to the point where I can't serve", said the 36-year-old after withdrawing from the match.
And don't expect the moment to get to Halep-She knows the rules of engagement. "In tennis, you never know, so I will stay chill". It would be very odd, I think, if I didn't write anything about her. Stephens won that one, as well as the only other match the longtime friends, Fed Cup and Olympic teammates have played against each other.
She was quoted as saying: "The book was a lot about me.I think the book was 100 per cent hearsay".
Regardless of the result, the 25-year-old Stephens will become the first American to break into the top five in the WTA rankings since Lindsay Davenport - Keys's coach - in 2006.
This time previous year, Stephens was still sidelined with a foot injury that her walking around in crutches and Keys was coming off a second wrist surgery. "And I am very motivated out there too - it was a Grand Slam quarter-final".
Furthermore, Halep's data on return yesterday was similarly strong, creating 17 break points on the usually strong Kerber serve across 15 return games, and it took a resolute performance by the German to take that first set to a breaker. "It was before because I really wanted to get there, but now my goals are different".
Halep and Stephens won straight-set matches in the semifinals. Over the last two sets, Halep made 16 unforced errors, half as many as Kerber, who was treated for a blister on her left foot early in the third.