Four-time champion Lleyton Hewitt was a quarterfinal upset winner Friday at the $900,000 Aegon Championships, a grass-court Wimbledon tune-up.
The unseeded former world No. 1 from Australia upended third-seeded fellow former U.S. Open champion Juan Martin del Potro of Argentina 6-2, 2-6, 6-2 at The Queen's Club.
The former Wimbledon champion Hewitt was the Queen's Club titlist from 2000-02 and again in 2006.
His semifinal opponent on Saturday will be reigning Queen's Club champ Marin Cilic. The fifth-seeded Croat also posted an upset by dousing second- seeded former Wimbledon runner-up Tomas Berdych of the Czech Republic 7-5, 7-6 (7-4) on Day 5.
Cilic beat former Wimbledon runner-up David Nalbandian in last year's Queen's Club final, which was defaulted by Nalbandian in the second set when the Argentine smacked an on-court advertising panel into a linesman, who suffered a gash on his leg during the mishap.
The 2013 Queen's Club titlist will earn $115,000.