<p>Spanish 10th seed Garbine Muguruza was bundled out of the US Open second round on Thursday, losing in straight sets to the returning Tsvetana Pironkova.</p>.<p>Pironkova, who made a comeback to tennis this year after a three-year break following the birth of her son, stunned two-time Grand Slam singles winner Muguruza 7-5, 6-3 in 1hr 25min.</p>.<p>Pironkova, who does not have a world ranking due to her long absence from the circuit, will now face Croatian 18th seed Donna Vekic in the third round.</p>.<p>Vekic advanced to the last 32 on Thursday with a 6-2, 6-1 defeat of Romania's Patricia Maria Tig.</p>.<p>Prior to this week, Pironkova, 32, had not played in a Grand Slam or any event since her appearance at Wimbledon in 2017, when she lost in the second round of a tournament eventually won by Muguruza.</p>.<p>Thursday's victory marks only the second time that Pironkova has reached the third round of the US Open in 12 appearances stretching back to 2005.</p>.<p>Pironkova's best performance in a Grand Slam came in 2010, when she reached the semi-finals at Wimbledon.</p>
<p>Spanish 10th seed Garbine Muguruza was bundled out of the US Open second round on Thursday, losing in straight sets to the returning Tsvetana Pironkova.</p>.<p>Pironkova, who made a comeback to tennis this year after a three-year break following the birth of her son, stunned two-time Grand Slam singles winner Muguruza 7-5, 6-3 in 1hr 25min.</p>.<p>Pironkova, who does not have a world ranking due to her long absence from the circuit, will now face Croatian 18th seed Donna Vekic in the third round.</p>.<p>Vekic advanced to the last 32 on Thursday with a 6-2, 6-1 defeat of Romania's Patricia Maria Tig.</p>.<p>Prior to this week, Pironkova, 32, had not played in a Grand Slam or any event since her appearance at Wimbledon in 2017, when she lost in the second round of a tournament eventually won by Muguruza.</p>.<p>Thursday's victory marks only the second time that Pironkova has reached the third round of the US Open in 12 appearances stretching back to 2005.</p>.<p>Pironkova's best performance in a Grand Slam came in 2010, when she reached the semi-finals at Wimbledon.</p>