Iga Swiatek continued her sublime recent form as she beat Great Britain's Emma Raducanu 6-4 6-4 to reach the Stuttgart Open semi-finals.

The pair traded breaks early in the second set but 20-year-old Swiatek secured another break to close out the match in straight sets.

The win was the new world number one's 21st victory in a row.

The success also saw her take her run of winning sets to 28 in a row, although Raducanu - playing in her first clay-court quarter-final - did offer stiff resistance in a match that lasted one hour and 45 minutes.

"Playing here is never routine as the surface is really tricky and I am using every minute to get to know it," said Swiatek after her first professional meeting with Raducanu.

"I am happy today's match was longer as I feel not for now but in the future it will give me a lot of experience."

Superb Swiatek at ease at the top

Swiatek - who won her only Grand Slam title on clay at the French Open in 2020 - moved top of the world rankings when Australia's Ashleigh Barty announced her retirement in March.

He recent form appears ominous for challengers at this year's French Open - which begins on 22 May - and she says she feels at ease despite the pressure that comes with her growing reputation.

"For me it doesn't really matter," said Poland's first world number one. "When I reached number one it was surprising for me. I didn't change.

"When I was an underdog for the past three years I felt like playing as an underdog was easier as you can play without pressure. As soon as I felt like I learned enough to be comfortable as the one who is seeded or with a better ranking, it feels fine honestly."

Swiatek found what she needed at key moments under pressure from 19-year-old Raducanu, notably in saving four of the five break points the Briton earned.

Raducanu - who needed a medical time out when trailing 2-1 in the second set - will rue being unable to take two break points when trailing 4-3 in the final set, and a further two when Swiatek was serving for victory at 5-4.

Winning the title in Stuttgart would have lifted world number 12 Raducanu into the top 10 for the first time.

But defeat means she has lost her two matches against opponents ranked higher than her since landing her shock US Open win, with this one following her 6-1 6-0 defeat by Elena Rybakina at the Sydney Tennis Classic in January.