PARIS: Czech left-hander Petra Kvitova reached the French Open quarter-finals for the first time in eight years as she overpowered China's Zhang Shuai 6-2 6-4 on Monday. On yet another chilly day in the French capital, seventh seed Kvitova's superior firepower proved decisive as she posted her fourth successive straight-sets victory. With so many big names already out, twice Wimbledon champion Kvitova will sense a golden title opportunity as she heads into a quarter-final against unseeded German Laura Siegemund. 'It was a great one today for sure,' said Kvitova, who returned to action at the 2017 French Open following a knife attack six months earlier that left her with career-threatening hand injuries. 'To be back on the same court that I made my comeback and to make the quarter-final is something I didn't expect. I'm trying to play faster here and play aggressive off the returns,' she told Eurosport. The 30-year-old, whose best finish here was reaching the 2012 semi-finals, made her intentions clear from the start as she seized on anything short to dominate from the baseline, moving 4-0 ahead in 15 minutes on Court Philippe Chatrier. Zhang, in the fourth round of a Slam for only the third time in 33 attempts having also not dropped a set so far, finally began to dig her heels in as Kvitova's error-count increased but she was unable to turn the tide. Kvitova had to wait around in the cold as Zhang took a medical timeout at the end of the first set, but she turned up the heat to get an early break in the second set. She broke again to lead 5-2 but some wild errors allowed the Chinese to win two straight games and create some tension. Kvitova regained her focus though to seal victory with a love service hold. World number 66 Siegemund, the oldest player left in the draw at 32, beat Spain's Paula Badosa 7-5 6-2 to reach her first Grand Slam quarter-final.