Dayana Yastremska delivered a polished performance as the Ukrainian kept her "very emotional" run going at the Lyon Open.

The 21-year-old broke serve five times on her way to a 6-2 6-3 victory over Spain's Cristina Bucsa in an hour and five minutes, booking a quarter-final place.

Yastremska fled war-ravaged Ukraine last week, along with sister Ivanna, escaping through Romania but leaving their parents behind in Odessa after Russia's invasion began.

The three-time WTA tournament winner has spoken of the decision by her mother to stay with her father, and how that left the sisters tearful and agonising over when the family might be reunited.

Yastremska began her campaign in Lyon with a gruelling three-set win over Ana Bogdan and followed up impressively by sweeping aside Bucsa.

"Today, definitely it was a little bit easier. With my emotions, I could keep them under control, so I'm very happy with that," Yastremska said in an on-court interview, broadcast on Amazon Prime.

"I tried yesterday to recover myself as fast as possible to prepare for my match today. Still, I was very nervous because I wanted to win the match for my country.

"This tournament is very emotional for me, but I'm very happy with the win today. To be honest I'm very happy that I'm here, that I'm in a safe place with my sister."

The former world number 21, now down at 140 in the WTA rankings, was joined in the last eight by Zhang Shuai of China and France's Caroline Garcia.

Also going through to the quarter-finals on Thursday was Vitalia Diatchenko, a Russian playing under a neutral flag this week. She beat Swiss third seed Viktorija Golubic in three sets.