Defending champion Marin Cilic upset second-seeded Tomas Berdych 7-5, 7-6 (4) to reach the Queen's Club semifinals on Friday.
The fifth-seeded Croatian faced a break point at 4-4 in the first set. But Berdych netted his return, and Cilic failed to convert two set points at 5-4 before Berdych made a forehand error on a third break point at 6-5.
In the second set, Berdych held one break point at 2-2 and another at 4-4. But Cilic once again held off the threat before claiming victory in the tiebreaker.