Defending champion Maria Sharapova admits she had atough opening in her bid to win a third straight Stuttgart WTA tournament title afterher three-sets win over Lucie Safarova.Sharapova, who has never lost on her two appearances in Stuttgart after winningthe 2012 and 2013 titles, will face Russia's Anastasia Pavlyuchenkova in Thursday'slast-16 tie after beating Czech Republic's Safarova 7-6(7/5), 6-7(5/7), 7-6 (7/2) late on Tuesday.Sharapova had to dig deep having been just two points away from defeat whenSafarova levelled at 30-all with the scores at 6-5 in the decisive third set.The statuesque Russian, the sixth seed in Stuttgart, needed three hours, 24 minutesfor the 100th clay-court victory of her career."I hadn't expected that it would be an easy match," said Sharapova, three days afterher 27th birthday."There were ups and downs, but the level was good from both of us."The momentum changed hands a couple of times."I'm happy that I'm the winner, because at one stage in the third set I was only twopoints away from defeat."Earlier Pavlyuchenkova defeated Latvian qualifier Diana Marcinkevica 6-3, 6-2 to setup her clash with Sharapova for a quarter-final place.Former world number one Jelena Jankovic, the fifth seed, saved four match points toreach Thursday's last 16 when she came back to claim a 2-6, 7-6 (10/8), 6-3 win overGerman lucky loser Mona Barthel.Jankovic will now face either German wild-card Andrea Petkovic or Italy's FlaviaPennetta for a place in the quarter-finals. Source: AFP