Hertogenbosch - Simona Halep's preparations for Wimbledon were cut short at the WTA/ATP 's-Hertogenbosch Open on Wednesday as she retired from her second-round match against Germany's Annika Beck with a shoulder injury.
Top seed Halep, who reached the final of the French Open where she was narrowly defeated by Maria Sharapova, won the first set 7-5, but the defending champion brought a premature end to the contest as she pulled out trailing 2-3 in the second set.
The Romanian received treatment on her right shoulder before retiring and will be hoping for a swift recovery ahead of next week's Grand Slam at the All England Club where she is the third seed.
Fourth seed Carla Suarez Navarro was another injury casualty as the Spaniard was forced to retire with a back problem having lost the first set to China's Zheng Jie, 7-5.
The seeds continued to fall on Wednesday as Belgium's Kirsten Flipkens, the sixth seed, succumbed to a 7-6 (7/4), 6-4 defeat against Ukrainian Elina Svitolina.
Klara Koukalova was the lone seeded player to advance to the quarter-finals on Wednesday after beating German qualifier Mona Barthel 6-2, 7-6 (8/6).
The eighth-seeded Czech joins seventh seed Garbine Muguruza, the highest-ranked player left in the draw, in the last eight and will face Yaroslava Shvedova for a place in the semis after the Kazakh beat Dutchwoman Michaella Krajicek 7-6 (8/6), 7-6 (7/4).
World number 27 Muguruza, who reached her first Grand Slam quarter-final at Roland Garros, will play Coco Vandeweghe as the American progressed following the third-set retirement of compatriot Vania King.
Fernando Verdasco is through to the men's quarter-finals after seeing off Dutchman Jesse Huta Galung 7-5, 6-3.
The 23rd-ranked Spaniard, the top player in the draw, will face Juergen Melzer of Austria next after the eighth seed recovered from a set down to beat Slovak qualifier Lukas Lacko 5-7, 6-3, 6-3.
Also through to the last eight was third seed Roberto Bautista Agut, who was a 7-5, 7-6 (7/1) winner over Australian Matthew Ebden.
Defending champion Nicolas Mahut of France remained in the running to retain his title after defeating American Steve Johnson 6-2, 7-6 (7/4).
However, fifth seed Dmitry Tursunov withdrew from his tie against home hopeful Thiemo de Bakker with a foot injury.
Collated results from the fourth day of the 's-Hertogenbosch ATP/WTA Open on Wednesday (x denotes seed):
Joao Sousa (POR) bt Mate Pavic (CRO) 6-2, 6-4
Thiemo de Bakker (NED) bt Dmitry Tursunov (RUS x5) w/o
Benjamin Becker (GER) bt Dudi Sela (ISR) 6-2, 7-5
Vasek Pospisil (CAN x6) bt Jan-Lennard Struff (GER) 6-4, 6-2
Nicolas Mahut (FRA x7) bt Steve Johnson (USA) 6-2, 7-6 (7/4)
Roberto Bautista Agut (ESP x3) bt Matthew Ebden (AUS) 7-5, 7-6 (7/1)
Jurgen Melzer (AUT x8) bt Lukas Lacko (SVK) 5-7, 6-3, 6-3
Fernando Verdasco (ESP x2) bt Jesse Huta Galung (NED) 7-5, 6-3
Annika Beck (GER) bt Simona Halep (ROM x1) 5-7, 3-2 ret'd
Elina Svitolina (UKR) bt Kirsten Flipkens (BEL x6) 7-6 (7/4), 6-4
Jie Zheng (CHN) bt Carla Suarez Navarro (ESP x4) 7-5, 0-1 ret'd
Klara Koukalova (CZE x8) bt Mona Barthel (GER) 6-2, 7-6 (8/6)
Coco Vandeweghe (USA) bt Vania King (USA) 6-7 (6/8), 6-0, 2-1 ret'd
Yaroslava Shvedova (KAZ) bt Michaella Krajicek (NED) 7-6 (8/6), 7-6 (7/4)