Harriet Dart says being happier in her personal life has helped her tennis improve after she thrashed Camila Osorio to reach the Birmingham Classic second round.

Dart will now face former Wimbledon champion and second seed Simona Halep.

"It's like any job - if you bring things from home into the workplace, it's very challenging," she said.

Dart, 25, has had a breakthrough year, including reaching her first WTA quarter-final at the Nottingham Open last week.

She also entered the top 100 for the first time after her run to the Indian Wells fourth round as a qualifier.

"I went through a bad relationship, it was very toxic, and I do believe, if you're happier off the court, you're happier on the court," added world number 106 Dart.

"I'm a lot happier now, I have a nice boyfriend now, which is nice. I definitely feel like I belong a lot more.

"It's not just about doing well here, it's about doing well the whole year. I feel like I've made steps in that way."

Dart will face a tough task against former world number one Halep, who is playing in her first grass-court event since winning Wimbledon three years ago.

Halep, 30, did not defend her title at SW19 last year after injuring her calf, but put in an aggressive performance to beat Ukraine's Lesia Tsurenko 6-1 6-4.

"I saw [Dart] playing lately. She's doing great so it's going to be difficult," Halep said.

"On grass it's different, everything is different and she's used to it, she's from here, so it's going to be a big challenge."

Donna Vekic and Elena-Gabriela Ruse also advanced on the opening day in Birmingham.

Croatia's Vekic, runner-up in 2013, beat American Coco Vandeweghe 6-4 6-4, while Romania's Ruse came past Wang Qiang of China 7-6 (8-6) 7-6 (14-12).

France's Caroline Garcia beat Viktorija Golubic of Switzerland 6-7 (5-7) 6-4 7-6 (8-6).

Birmingham is the penultimate WTA event in the UK before Wimbledon begins on 27 June.