Anne Keothavong welcomed her improvement as she battled past Pauline Parmentier in the AEGON Classic in Birmingham on Wednesday- but there was misery for British number one Elena Baltacha.

Keothavong was given a major test by France's Pauline Parmentier before coming through 4-6 7-5 7-5. The Londoner was a break down in the deciding set but pulled through and was scheduled to meet top seed Li Na.

"It was a tough match but I'm glad I got through in the end," said Keothavong. "I just had to hang in there. My first-serve percentage wasn't where I'd like it to be and she had her chances but I toughed it out in the end.

"My level picked up in the final set. I changed it up and once I got a feel for the courts I got better."

Baltacha continued her good form in 2010 by winning the ITF title in Nottingham last week but it came at a cost as she was laid low by heatstroke.

The Scot admitted earlier in the week she was struggling to recover and she called it a day after losing the first set 6-1 to Estonia's Kaia Kanepi.

The sixth and the eighth seeds both exited the tournament at the second-round stage.

Yaroslava Shvedova, a quarter-finalist at the French Open, lost 6-4 6-4 to qualifier Sesil Karatantcheva while Anna Chakvetadze knocked out Andrea Petkovic by the same scoreline.

There were few problems for number five seed Sara Errani, who beat Shenay Perry 6-2 4-6 6-1, while Magdalena Rybarikova, Angelique Kerber and Alla Kudryavtseva all reached round three.

Second seed Maria Sharapova won the first four games against Bethanie Mattek-Sands before the rain came, while Aravane Rezai was an early break up on Anastasia Rodionova at 2-0.

The favourites were struggling elsewhere, though, with seventh seed Olga Govortsova losing the first set 6-1 to Portuguese teen Michelle Larcher de Brito - although the Belarusian was 3-1 up in the second.

India's Sania Mirza won the first set 6-4 against 14th seed Tamarine Tanasugarn, while American qualifier Alison Riske was 4-2 up against ninth seed Aleksandra Wozniak.