STUTTGART, April 21 — World number one Iga Swiatek reached the quarter-finals of the WTA Stuttgart event with a straight-sets win over Zheng Qinwen yesterday on her return from injury.

The Pole won 6-1, 6-4 as a dominant first set put her on course for victory in just under 90 minutes at the clay-court tournament.

"I felt like I needed to be 100 per cent focused from the beginning to the end, to think about technique and tactics,” Swiatek said.

"I’m pretty happy that I’m not rusty and I could perform good tennis, even though I had a break.”

After Zheng broke to lock the second set at 4-4, the two-time French Open winner broke back immediately and then served out the match.

"She’s really talented, and everybody can see that,” Swiatek said of her Chinese opponent.

"I needed to adjust, and I’m just happy that I was focused on myself, on what I wanted to do ... and I feel pretty comfortable. So I’m happy that I could show my good tennis.”

Swiatek withdrew from the Miami Open and Billie Jean King Cup qualifiers with a rib injury, but told reporters on Wednesday: "I’m not injured anymore.”

Coco Gauff’s French Open warm-up stalled as last year’s Roland Garros runner-up fell in the last 16 to Anastasia Potapova.

The Russian impressed with her returning game to dominate the American, winning 6-2, 6-3.

World number six Gauff, who made it past Potapova’s compatriot Veronika Kudermetova in three sets despite an error-ridden second-round performance on Wednesday, converted none of her six break points against Potapova.

Potapova, ranked 24th, is competing in Stuttgart for the first time with the 22-year-old advancing to her fourth quarter-final of the year.

Wimbledon champion Elena Rybakina was forced to retire from her last-16 clash with Beatriz Haddad Maia of Brazil.

The 26-year-old Haddad Maia was ahead 6-1, 3-1 when her seventh-ranked opponent quit with an injury.

Czech former world number one Karolina Pliskova fought past Croatian Donna Vekic 6-2, 6-7 (5/7), 7-6 (7/5).

Pliskova, who won the Stuttgart title in 2018, will face Swiatek today for a place in the semi-finals. — AFP