DALLAS, TX, USA - No.2 seed Jelena Jankovic was made to work hard for her place in the second round of the Texas Tennis Open on Monday evening, coming from a set down to defeat Yaroslava Shvedova in a three-hour marathon.

After Angelique Kerber's late withdrawal, Jankovic is now the highest seed in the tournament, but she came within a handful of points of falling at the first hurdle against Shvedova.

Staring over the precipice with Shvedova serving for the match in the second set, though, Jankovic suddenly sparked into life, reeling off the next four points and the tie-break that followed to take a decisive stranglehold of the match.

A shell-shocked Shvedova had no answer to the newly focused Jankovic, who found the consistency lacking in the first two sets to race through the decider.

Jankovic has struggled for form this summer, falling early in her last seven tournaments, and was understandably pleased with the 67(7) 76(4) 61 win. "I got a lot of practice in that first match" she said. "It was a good match and I'm happy I was able to win at the end.

"The first two sets were so close, but I managed to tough it out, fighting for every point and then in the third set I started to play much better. I was returning much better and also much more solid, making her work for every point and this really helped me get over the line."

Also forced to come from a set down was No.6 seed Peng Shuai. Taking on Ayumi Morita, Peng overcame the shock of losing the opening four games, to slowly work her way back into the match and eventually run out a 46 60 63 victor.

"I don't think I played so well in the first set because I really wasn't used to the match court," Peng said. "I couldn't really feel the ball and was playing really badly on all the game points.

"Towards the end of the first set I was feeling like I was playing better and I continued this into the second set and also the final set."

The only other seed in first round action, Roberta Vinci, enjoyed a far easier time of things, making short work of Hsieh Su-Wei, 62 62. While Vinci was racing through her match, over on Grandstand 1, Marina Erakovic and Anne Keothavong were busy posting an early contender for match of the tournament.

Eventually, after nearly three hours on court, it was Erakovic who prevailed, 61 57 76(9), having recovered from 5-3 down in the third set and fending off five match points in the deciding tie-break.

There were also wins for qualifiers Pauline Parmentier, Mirjana Lucic, Casey Dellacqua and Eugenie Bouchard.