Roddick faces big serving Isner in semi-finals

Raleigh: Andy Roddick and John Isner set up a mouth-watering semi-final between two big servers after the Americans won their respective quarter-final matches at the Winston-Salem Open on Thursday.

Top-seeded Roddick crushed seventh seed Juan Monaco of Argentina 6-1 6-4 while fourth seed Isner recovered from a shaky start to beat eighth-seeded Cypriot Marcos Baghdatis 1-6 6-3 6-4.

Roddick enjoys a 3-1 advantage in career meetings with the towering Isner but he predicted a tough encounter in the last four with his six-foot nine-inch compatriot.

Meanwhile, top ranked Caroline Wozniacki cruised into the next round and China's Li Na had to endure a rain delay before booking her spot in the semi-finals of the New Haven Open on Thursday.

Wozniacki remained undefeated advancing with a 7-5, 6-3 win over American teenager Christina McHale.

Li scored a 6-4, 3-6, 6-2 victory over Russia's Anastasia Pavlyuchenkova.