No.2 seed Garbiñe Muguruza of Spain eased into the Chicago Fall Tennis Classic semifinals on Friday, ending the breakthrough run of Japanese qualifier Mai Hontama, 6-3, 6-2.

It took Muguruza an hour and 40 minutes to stop Hontama's winning streak, putting the former World No.1 into her fourth semifinal of the season.

"It was a tough match because I didn't know much about her," Muguruza told the press, after her win. "I think she has a lot of confidence right now, it was a tricky match."

"But I'm very happy," Muguruza continued. "I think that the first set was key, because it was very tough. She came back from 4-0 down, and managed to make the end of the first set very tight. Then in the second set, I managed to escape and get an early break, so very happy to be able to close the match in two sets."

Stat corner: World No.200 Hontama had a stirring run to the quarterfinals this week in the first WTA main-draw appearance of her career.

The 22-year-old Hontama had never played a Top 100 foe before this event, but notched two Top 60 wins en route to the elite eight, defeating Caroline Garcia in the first round and Shelby Rogers in the third round. 

But World No.9 Muguruza had the answers against the Japanese player, breaking Hontama's serve seven times by collecting 75 percent of the qualifier's second-service points.

Muguruza out-winnered Hontama by 13 to 5, as the Spaniard is still in the hunt for her second title of the year, having beaten Barbora Krejcikova for the Dubai crown during the winter. Muguruza is also in contention for a coveted spot at the WTA Finals, currently sitting at No.8 in the Porsche Race.

Story of the match: Despite the relatively breezy scoreline, Hontama acquitted herself well throughout, pushing Muguruza into numerous long games. With the Spaniard leading 4-1 in the first set, Hontama earned her first break of the day with a backhand winner down the line, putting Muguruza on notice.

Muguruza countered with exceptional grit, grinding out a tough hold for 5-3 before earning her third service break of the opening frame to close out the set one game later. Muguruza’s eight winners doubled Hontama’s winner total in the first set.

After four consecutive service breaks opened the second set, Muguruza took command by forcing an error with her forehand to move ahead 4-2 on her third break point of that game.

Hontama again dragged Muguruza into two more lengthy games, but Muguruza was able to prevail in each: she needed five match points in the final game, but took the fifth with a big backhand.

Next up: Muguruza will now take on Olympic silver medalist Marketa Vondrousova of the Czech Republic in the final four. In their lone previous meeting, Muguruza dismantled Vondrousova 6-1, 6-0 in the Yarra Valley Classic semifinals in Melbourne in January.

Muguruza powers through Hontama, into semis: Chicago Highlights

2021 Chicago 500

Vondrousova vanquishes Collins: Vondrousova outlasted No.10 seed Danielle Collins of the United States in the first quarterfinal of the day, 6-7(4), 6-0, 7-6(3), as the Czech moved into her fourth semifinal of the season.

"We were both fighting very much from the beginning," said Vondrousova. "I felt like the first set was 50/50, and then I started serving really well, and I think she was a bit down, but I knew she was coming back for the third set. And then it was just pure fight, so I'm happy to be through."

The first meeting between the two proved to be a topsy-turvy clash, with World No.41 Vondrousova winning in a tense 2 hours and 32 minutes, after 28th-ranked Collins had served for the match at 6-5 in the third set.

Collins was the aggressor more often than not, but Vondrousova played the cleaner match as a whole, with 26 winners to just 17 unforced errors. Collins’s 33 winners were slightly outpaced by 36 unforced errors. Vondrousova also won 85 percent of her first-service points to help her eke out the win.

An epic was portended by the first game of the tilt, where Collins hit three double faults and had to stave off six break points, but held serve anyway.

All-court play by both propelled them into a first-set tiebreak, where Collins slammed an ace to take an initial 4-1 lead. A missed return by Vondrousova gave Collins three set points at 6-3, and the American used blistering backhands to notch the second of that trio.

However, that grueling set took its toll on Collins, while Vondrousova flourished in the second set. The Czech fired eight winners to just a single unforced error in that set as she raced to the bagel in 23 minutes, leveling the match.

The two went toe-to-toe in the final set, with Collins going up a break at both 4-3 and 6-5, with the latter meaning that Collins would serve for the match. But Vondrousova drew errors from the American in that game to break quickly, queuing up a decisive tiebreak.

A Vondrousova winner off of a Collins dropshot gave the Czech an early mini-break for a 2-1 lead, and Vondrousova would not yield on her serve for the rest of the breaker, taking it home for the victory.