NEW HAVEN, Conn. (AP) -- Martina Hingis' second tournament since returning from ankle surgery started out positively, but with a struggle.

The fifth-seeded Hingis beat Anna Smashnova 6-4, 6-4 Monday night at the Pilot Pen.

After coming out strong in the first set and going up 5-0 in the second, the former world No. 1 battled to put away Smashnova.

After six match points, two breaks, several missed volleys and huge exertions by Smashnova, Hingis won the match to advance to the second round at the Connecticut Tennis Center.

``I think this year I have a little match point problem,'' Hingis said.

Hingis said her left ankle felt ``fine.'' She sat out much of this season after having the surgery to repair a damaged ligament.

Hingis said she tried to do different things to score points off Smashnova, whom she has not played for years, but Smashnova kept surprising her by returning the shots.

``I had to look for the strategy of her,'' Hingis said. ``I realized I really had to fight and earn it.''

Hingis also struggled with her power serve -- most attempts at serves above 90 mph landed in the net.

Still, she said she was pleased with her first-shot percentage and her ability to keep up with Smashnova, who won this year at Vienna and Canberra.

In the biggest upset of the first round, qualifier Angelika Roesch survived some long rallies and beat No. 8 seed Elena Dementieva 6-3, 1-6, 6-3.

After losing the first set, Dementieva came out strong in the second, serving aces and capitalizing on Roesch's errors. She lost the first three games in the third and tried to battle back.

Roesch went ahead with a solid serve, while Dementieva's faltered. She still took time to close out the match, failing on six match points before hitting a sharp baseline shot past Dementieva for the win.

``It was not very easy to finish, and also, I was a little nervous at the end,'' Roesch said.

Roesch beat Dementieva in three sets earlier this year in Berlin.

``I knew how she was playing, and I got a good rhythm against her,'' Roesch said.

Also advancing was qualifier Elena Bovina, a 4-6, 6-1, 6-2 winner over wild card Lisa Raymond.

Another wild card entrant fared better: Alexandra Stevenson beat qualifier Jelena Kostanic 6-3, 7-5.

``She's a clay-courter, so she likes her angles. She throws up the ball and mixes it up, so she wasn't an easy qualifier -- that's for sure,'' Stevenson said.

Stevenson has struggled this year, losing in the first rounds of the French Open, Wimbledon, Stanford and San Diego.

She made it to the later rounds of Los Angeles and Montreal, and said she hoped to build on those improvement in New Haven.

``Hopefully, I'll be great for the (U.S.) Open, so I'm right on schedule -- you don't want to peak too early,'' Stevenson said.