LONDON -- American teenager Coco Gauff just keeps winning at Wimbledon.

After coming through qualifying and then upsetting five-time champion Venus Williams in the first round, the 15-year-old Gauff extended her stay Wednesday at the All England Club by dispatching former semifinalist Magdalena Rybarikova 6-3, 6-3.

Gauff is the youngest player to come through qualifying for Wimbledon in the Open era but showed her maturity once again in a match played under the new roof on No. 1 Court. She never faced a break point and had only 10 unforced errors compared to 24 for Rybarikova.

Meanwhile, eighth-seeded Elina Svitolina advanced to the third round after Margarita Gasparyan retired with a leg injury in the second set on Wednesday. Gasparyan was leading 7-5, 5-6 when she was forced to quit.

She had been on the verge of an upset, two points from the match at 5-4 in the second, but Svitolina held and her opponent was then injured after delivering a serve at 0-15 in the next game.

Gasparyan clutched her left thigh in pain, then remained lying on the baseline for several minutes getting treatment from a physical therapist, with Svitolina also coming over to bring her opponent water.

"I know when there is cramps, you need to drink lots of water," Svitolina said. "Your muscles are contracting. So it's important just to drink lots of fluids. So that's why I gave her some water, because no one really did anything. I mean, we were trying to help, but, yeah, it's tough to react straightaway."

Gasparyan, who has had three surgeries on her left knee since her last Wimbledon appearance in 2016, eventually got back up but was broken and then retired during the next game.

It's only the second time in eight appearances that Svitolina has reached the third round at the All England Club. Her best result was reaching the fourth round in 2017.

Former No. 1 Simona Halep also advanced, beating Mihaela Buzarnescu 6-3, 4-6, 6-2. She will next play Victoria Azarenka, who beat Ajla Tomljanovic 6-2, 6-0.

Third-seeded Karolina Pliskova advanced with a 6-0, 6-4 win over Olympic gold medalist Monica Puig.

Another unseeded American, Danielle Collins, also advanced. Collins beat No. 12 Anastasija Sevastova of Latvia 4-6, 6-4, 6-3.

The Associated Press contributed to this report.