NEW HAVEN, CT, USA - The first round wrapped up and the second round began Tuesday at the New Haven Open at Yale, one of two WTA events in this, the final week before the final Grand Slam event of the year, the US Open.

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The last first round match of the week saw two Grand Slam semifinalists do battle, and it was 2008 Wimbledon and 2010 Australian Open semifinalist Zheng Jie who came out the winner against 2010 Wimbledon semifinalist Tsvetana Pironkova, 75 62, though not before Pironkova came out strong - the Bulgarian twice led by a break in the first set, including serving for it at 5-4.

The second round kicked off and the biggest headline came at night, as the tournament's No.1 seed, Agnieszka Radwanska, was forced to retire against Olga Govortsova due to a right shoulder injury after falling behind, 60 21. Govortsova, a qualifier into the draw, won the first seven games of the match before Radwanska broke serve to get on the board in the second set, 1-1; but Govortsova broke right back in the next game and that was the end of it.

"I've been struggling with my shoulder for a couple of weeks now, pretty much since the start of the hardcourt season two weeks ago," Radwanska said to reporters. "I think maybe the change of surface and balls since coming from the Olympics was just too much, and I've played a lot this year as well.

"I'm going to go and have some rest now and hopefully be ready for Monday."

The other three seeds in action all advanced, with No.4 seed Sara Errani grinding past Carla Suárez Navarro, 64 63; No.5 seed Marion Bartoli losing nine games in a row to drop the second set and fall behind 3-0 in the third but bouncing back with six games in a row of her own to survive Sloane Stephens, 61 06 63; and No.7 seed Maria Kirilenko making it by Mona Barthel when the German withdrew from the tournament due to a gastrointestinal illness.

Errani talked about playing Suárez Navarro. "We know each other very well - we play a lot of time in matches and in practice," she said. "I played a good match today, I think. I like the courts here in New Haven - they're not too fast."

With Radwanska out, Errani is one of three Top 10 players left in the draw, along with Petra Kvitova and Caroline Wozniacki. But the Italian is the newest addition to the Top 10, and wasn't even in the Top 20 until her run to the Roland Garros final propelled her from outside the Top 20 into the Top 10, the first player in the history of the WTA Rankings to make that huge leap.

"Before Roland Garros I didn't have a Top 10 win in my life, then I had two there, then I was Top 10 myself," Errani said. "Now when I go on the court, more times I'm the favorite in the match. It may be more pressure, but if you can work that pressure to your advantage, it can really be an advantage for you.

"But I still want to work more and more and get more and more."