Garbine Muguruza left a first impression Caroline Garcia will likely not forget as the new world No. 1 bounced the Frenchwoman out of the Toray Pan Pacific Open in straight sets on Friday.

Muguruza, making her debut as the WTA's top-ranked player and having validated her coronation in her first two matches at this tournament, rolled into the semifinals with a 6-2, 6-4 victory over Garcia in their first career meeting at Ariake Colosseum.

Garcia took the opening game of the match but Muguruza never trailed beyond that, winning the next five games. The 1 hour, 22 minute contest came to an end after the hard-hitting Garcia's shot sailed long on the second match point.

Muguruza returns to the last four for the first time since 2014, when the Spaniard lost to two-time Pan Pacs winner Caroline Wozniacki -- whom she will face Saturday.

Former No. 1 and defending champion Wozniacki went through 3-6, 7-6(5), 3-1 after fifth-seeded Dominika Cibulkova retired in the third set of a 2 hour, 27 minute marathon with a right-thigh injury.

"I felt my game was there, my intensity, and our tennis was a good match," Muguruza said. "I'm happy that in the important moments I played a little bit better."

"I'm very happy with this match. We never played before so it was difficult, but I'm back in the semifinals. I'm more the favorite, I guess, but I'm just trying to go out there and fight, give it everything I have because that's what counts."

Muguruza said she was looking forward to a little payback against Wozniacki.

"I remember that match well," Muguruza said. "She plays good here. She's won two times. I think it's a good challenge for me, to get that revenge back."

In a tense rematch of last year's U.S. Open final, Angelique Kerber got the better of Karolina Pliskova once again, edging the second seed 7-6(5), 7-5.

Kerber, who will face Anastasia Pavlyuchenkova in her semifinal, converted a fifth match point to beat an error-strewn Pliskova in a nail-biter that pitted two former world No. 1s.

There was just one break throughout the entire match, by Kerber in the final game.

"(Pliskova has) played an amazing year so far. I'm happy to win the match and be back in the semifinal," said the 14th-ranked German, whose previous best showing at the Pan Pacific Open was in 2013 when she reached the final.

"The match was on a high level from both of us. In the end, it was just one or two points that decided the match. I just broke her and that was the key at the end."

Neither gave in from the start of the first set, during which Pliskova saved three break points and Kerber two -- Pliskova saved 12 of 13 for the entire match, Kerber all five -- in forcing a tiebreak.

Kerber closed in on the set at 6-4, a point which Pliskova managed to save. But on the second set point, Pliskova, who planted five aces in the first set alone, double-faulted to hand the set to Kerber.

The second set was another test of perseverance and resolve for both players, in particular Pliskova who was visibly annoyed by her service game as the double faults piled up; the Czech had eight for the match.

Pliskova's frustration truly came to the fore early in the set, when she shot a glare into the stands at a fan who she appeared to think was heckling her. The fan, however, was actually rooting for Pliskova, shouting the Japanese cheer "Gambare!"

In the deciding 12th game from 40-15, Pliskova saved two match points to force deuce and two more to cling on. But on the fifth match point, she netted a close shot down the line as Kerber improved to 6-3 lifetime against Pliskova.

"It was just one break so it was very close. Even the tiebreak was very close," Pliskova said. "I think she just played a little bit better at some points. I made a few mistakes and two, three points decided it. When you play against someone who's that good, it's always about a few points."

"I'm not upset about my losing today. That's how it is."

Russia's Pavlyuchenkova defeated Barbora Strycova of the Czech Republic 5-7, 6-3, 6-1 after a brief rain delay. Pavlyuchenkova holds a perfect record of 4-0 against Strycova for her career.