In a highly anticipated quarterfinal at the Porsche Tennis Grand Prix on Friday, World No.1 Iga Swiatek of Poland overcame a stern effort by No.8 seed Emma Raducanu of Great Britain before triumphing 6-4, 6-4.

For Swiatek, the 1-hour and 45-minute victory over reigning US Open champion Raducanu marks her 21st straight match-win. It is also the Polish star’s tour-leading 28th victory of the season thus far.

"I'm not thinking much about what's happened, and also what's going to happen," Swiatek said, after yet another victory. "[I'm] just focusing on the next match, and I'm really doing everything to prepare and recover well after each round. ... It seems like I'm going with the flow, but behind it, it's hard work."

Photo by WTA

Iga keeps rolling: Swiatek’s latest win extends more of the streaks she is currently carrying as well. For starters, Swiatek now has won her last 13 matches in straight sets. The last set she dropped came against Angelique Kerber in the Indian Wells Round of 16 over a month ago.

By defeating World No.12 Raducanu, Swiatek has also won her last seven matches against Top 20 opposition. Her last loss against a Top 20 player came to then-No.1 Ashleigh Barty at Adelaide in January.

Moreover, Swiatek is now 4-0 against British players in her pro career. Before topping Raducanu on Friday, Swiatek defeated Heather Watson at 2019 Toronto qualifying and 2021 Eastbourne, and beat Harriet Dart at this year’s Australian Open.

Raducanu, who won her first two clay-court matches at a Hologic WTA Tour event this week, acquitted herself well in her first match against a Top 10 opponent. After nearly two tight sets, Raducanu had two chances to break serve in the last game of the clash before Swiatek claimed the last semifinal spot.

More from Stuttgart: Badosa, Sabalenka to play in Stuttgart semifinals

Match moments: Swiatek broke Raducanu in the opening game of the match, and the Pole held that lead the whole way through the first set. The players had an equal number of unforced errors in the first set, but Swiatek had nine more winners during that timeframe.

Raducanu, though, continued to press in the following set, earning her first break of the day in the second game. However, Swiatek used her deep, heavy shots to push Raducanu back in rallies and was rewarded with another break for a 2-1 lead.

Swiatek again held that advantage up to 5-4, but the top seed was tested in that game, when Raducanu's defense drew Swiatek into errors. Swiatek had to stare down two break points at 15-40, but the Pole withstood them before converting her second match point with a sturdy forehand.

In the semifinals, Swiatek will meet big-hitting Liudmila Samsonova, in their first meeting.

"I've seen the scores, and it seems like [Samsonova] is getting more and more confident, and her ranking is going up," said Swiatek. "So for sure she's one to watch, and she's doing huge progress. ... I need to tactically prepare tomorrow, and I'll be ready."

Samsonova ousts former champion Siegemund

Earlier on Friday, Samsonova knocked out the last remaining German with a 7-5, 6-3 win over 2017 Stuttgart champion Laura Siegemund.

"I knew that it was going to be a very tough match," Samsonova said. "The way she plays, she changes her game a lot, so I had to be very, very focused today."

World No.31 Samsonova is into her first semifinal of the year after her 1-hour and 48-minute victory over wildcard Siegemund. Samsonova continues to post some of her best results in Germany; she won her breakthrough title at WTA 500 Berlin last summer as a qualifier.

Highlights: Samsonova def. Siegemund

Former Top 30 player Siegemund is on the comeback trail after returning from a right leg injury, and she picked up her first tour-level singles wins of the season this week. However, her run ended at the hands of Samsonova, who won two-thirds of points returning the Siegemund second serve.

A long first set was cracked open at the end by Samsonova, who took the last two games of the opener by using furious forehands to force errors from Siegemund on game points.

Samsonova took the early lead in the second set with a break for 2-1, then claimed another break for good measure in the last game of the clash, at love.