Muller, Isner advance to Atlanta semifinals

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.

Gilles Muller of Luxembourg returns a forehand to Tommy Paul during the Atlanta Open at Atlantic Station.

Gilles Muller, coming off a Wimbledon quarterfinal run and upset of Rafael Nadal, reached the ATP BB&T Open semifinals 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.

Third seed Muller booked a Saturday matchup against US second seed John Isner, a three-time Atlanta champion who fired 13 aces to oust Slovakia's Lukas Lacko 7-5, 6-4.

Lacko second double fault of the match gave Isner the first break chance of the second set and the American took advantage for a 5-4 lead, then held serve to finish off his 129th-ranked foe after 73 minutes.

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.

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.

Isner, ranked 20th, won both prior matches against 129th-ranked Lacko, in 2014 at Auckland in and in a 2014 Davis Cup tie.

He owns a 3-2 career record against Muller, including three-set wins in the 2010 second round and 2011 semi-finals at Atlanta plus another in 2012 at Memphis.

Muller won their most recent meetings in the third round of the 2015 Australian Open and the round of 16 last year at Queen's.

Isner seeks his 12th career title and second of the year after last week's Hall of Fame Open.

Isner, who played college tennis in Georgia just up the road from Atlanta, was a 2010 and 2011 Atlanta runner-up before winning titles in 2013, 2014 and 2015 only to fall to Aussie Nick Kyrgios in the 2016 final.

In later quarterfinals, US top seed Jack Sock was set to face British fifth seed Kyle Edmund and American fourth seed Ryan Harrison was to play compatriot Christopher Eubanks.