JOIN USWawrinka shocked by World No 259
Three-time Grand Slam champion Stan Wawrinka blew a one-set lead to fall 4-6, 6-3, 6-2 to unfancied Dutchman Tallon Griekspoor in a first-round shock at the Rotterdam Open.
The Swiss fifth seed slumped to another surprise defeat by an outsider, after losing in the Australian Open second round to Tennys Sandgren and in last week's Sofia Open semifinals to Bosnian Mirza Basic.
The 32-year-old Wawrinka, the 2015 Rotterdam winner, is struggling to regain top form after a pair of summer knee operations.
The Swiss has now lost three matches and won three since returning in January.
World number 259 Griekspoor, 21, earned the biggest success of his career as he competed in only his third ATP-level match.
Wawrinka's devastating single-handed backhand was of scant use to him on the night, with his movement still well below his best.
"It was a tough day at the office," Wawrinka said. "I still need a lot of work to get back."
Fourth-seeded David Goffin of Belgium, last year's runner-up, brushed aside Nicolas Mahut 6-1, 6-3 in straight sets to reach the last 16.
Earlier on Tuesday, ninth seed Gilles Muller of Luxembourg lost to Russian qualifier Daniil Medvedev 6-4, 7-6 (11/9).
Kvitova cruises
Double Wimbledon champion Petra Kvitova breezed through her Qatar Open first round match against Cagla Buyukakcay on Tuesday, losing just four points out of a total 28 played in the first set.
Kvitova -- currently ranked 21 in the world as she continues her return to top-class tennis following a horrific knife attack just over a year ago -- won 6-0, 6-3.
The first set took just 19 minutes to complete, the whole match less than an a hour.
Kvitova, who was left with tendon and nerve injuries to her left hand following the attack, said she was happy with her recovery.
"I think I'm still progressing and improving my game," she added.
"My hand has allowed me to improve what I can. And obviously it's a lot of hard work off the court and on the court as well.
World number 11, Britain's Johanna Konta, beat American Bernarda Pera 7-6 (7/5), 6-1 on Tuesday, getting instant revenge on the woman who surprisingly knocked her out of last month's Australian Open.
Also through was number four seed Garbine Muguruza who won 6-3, 6-4 against China's Duan Yingying.
And France's Caroline Garcia beat Slovakia's Dominika Cibulkova 6-3, 6-7 (3-7), 6-0.
Nishikori wins
Kei Nishikori returned to an ATP Tour level event for the first time since last August and cruised into the second round of the inaugural New York Open with a 7-5, 6-3 win over American wild card Noah Rubin on Tuesday.
The Japanese fifth seed, fresh off winning a Challenger event in Dallas, trailed 0-3 in the first set but pulled level and then never looked back against Rubin, who was playing in front of his hometown crowd in Uniondale.