Washington - Gilles Muller, coming off a Wimbledon quarter-final run and upset of Rafael Nadal, reached the ATP BB&T Open semi-finals on Friday by defeating US qualifier Tommy Paul 6-3, 6-1.
The 34-year-old Luxembourg left-hander blasted 16 aces to oust the 20-year-old world number 291 in only 69 minutes to advance at the Atlanta hardcourt tuneup event for the US Open.
Muller downed world number two Nadal in a five-set Wimbledon thriller earlier this month, winning 6-3, 6-4, 3-6, 4-6, 15-13 after four hours and 48 minutes to reach his first Grand Slam last-eight since 2008, falling to Marin Cilic in the quarters.
Third seed Muller booked a Saturday matchup against the winner of a later match between US second seed John Isner and Slovakia's Lukas Lacko.
Muller, ranked a career-high 22nd, seeks his third career ATP title and third title of the year after wins in January at Sydney and last month at Rosmalen.
He lost his first five career ATP finals from 2004 to last July and was also runner-up two months ago at Estoril.
In later quarter-finals, US top seed Jack Sock was set to face British fifth seed Kyle Edmund and fourth seed Ryan Harrison was set to face American compatriot Christopher Eubanks.