Ferrer and Clijsters win through
Top seed David Ferrer strolled into the quarter-finals of ATP Den Bosch with a 6-3 6-1 win over Leonardo Mayer.
The Spaniard, who has been seeded seventh for Wimbledon, made short work of his Argentine opponent.
However, third seed Juergen Melzer was knocked out, losing 6-3 6-2 to Tatsuma Ito. And number eight seed Lukasz Kubot was sent out after a topsy-turvy match against Benoit Paire - the Frenchman winning 6-3 0-6 6-4.
Other players to win through to the quarter-finals were Xavier Malisse, Gilles Muller, Igor Sijsling, Philipp Petzschner and Edouard Roger-Vasselin.
Kim Clijsters was among the players through to the last eight on the women's side of the draw, defeating Katerina Bondarenko 6-2 6-1. The unseeded Belgian faces Francesca Schiavone next.
Third seed Dominika Cilbulkova is the highest seed remaining, and beat Shahar Peer 6-2 7-6 to set up a quarter-final against Nadia Petrova.
The other quarter-finalists are Kirsten Flipkens, Roberta Vinci, Ursula Radwanska and Sofia Arvidsson.