Katie Boulter claimed the biggest win of her career by ranking as she beat Alison Riske to reach the Birmingham Classic second round.

Boulter has struggled with illness and injury over the past three years and is just returning from a leg injury she sustained in March.

"I just want to go out there, smile and have fun," Boulter said.

Boulter, who has been awarded a Wimbledon main draw wildcard, will face France's Caroline Garcia next.

She broke the serve of Riske, runner-up at last week's Nottingham Open, in the first game of the match and saved three break points before closing out the set.

Boulter then won the final four games of the second set to wrap up a fine victory.

"I feel like I've got close to a few of the top players and never got over the line," Boulter said in her on-court interview.

"I feel I can go out on the court and compete with anyone out there.

"A few of those under my belt and really kick on and I feel like I'll be in a good place."

Top seed Jelena Ostapenko overcame a mid-match wobble to beat Canada's Rebecca Marino.

The Latvian, a former Wimbledon junior champion, blew a 5-1 lead in the second set before regrouping to win 6-2 5-7 6-3.

"The biggest opponent to me was myself because I played really well until 6-2 5-1," Ostapenko said.

"She didn't really do anything, she didn't change anything, then I started to fight against myself, I started to miss some balls.

"I'm glad I won because my level is way better than hers today and I showed it. It was not one of my best matches. I think if I played really well today it would have been much easier for me."

Ukraine's Dayana Yastremska beat Magda Linette of Poland 6-4 6-3 but fourth seed Elise Mertens lost 3-6 6-4 7-5 to American Caty McNally.

Nottingham Open champion Beatriz Haddad Maia continued her strong start to the grass-court season with a 7-6 (7-4) 6-2 win over two-time Birmingham champion Petra Kvitova.