Xavier Malisse knocked out defending champion David Ferrer in the first round of the Topshelf Open in Den Bosch, Holland.
Belgian Malisse, a semi-finalist at Wimbledon 11 years ago, is always a dangerous player on grass and he reached the second round with a 7-6 (7-3) 6-3 victory.
World No 4 Ferrer won the event last year as part of an impressive month on grass that also saw him make the quarter-finals of Wimbledon.
In the day's other games, second seed Stanislas Wawrinka was a 7-6 (7-5) 6-4 winner over Steve Darcis but fourth seed Benoit Paire lost the first three games against fellow Frenchman Michael Llodra and then retired with a right leg problem.
There were no problems for fifth seed Jeremy Chardy, a 7-5 6-4 winner over Lucas Pouille while another Frenchman, Nicolas Mahut, beat Ricardas Berankis 6-1 6-4.
In the women's tournament, top seed Roberta Vinci kicked off her campaign with a 6-3 6-3 victory over Kaia Kanepi.
Daniela Hantuchova went into the event in great form after winning the Aegon Classic in Birmingham last week but she retired down 5-0 to Lesia Tsurenko.
Fourth seed Kirsten Flipkens came from a set down to defeat former French Open champion Francesca Schiavone while third seed Carla Suarez Navarro is through to the quarter-finals after beating Sofia Arvidsson.