Memphis: No. 1 seed John Isner hammered 26 aces en route to a 7-6 (7/1), 7-6 (7/4) victory over Gilles Muller in the first round of the Memphis Open on Tuesday.

The world number 13, who is chasing his fourth career title, clinched the victory by winning the final three points of the second set tiebreaker.

The 26-year-old Isner won 48 of 50 first-serve points and had just two double faults compared to nine double faults for the Belgian Muller in the 100 minute match.

Isner is also hoping to win his first title indoors. He lost in the 2010 final to fellow American Sam Querrey

Isner next faces Donald Young who advanced to the second round with a three set win over Grigor Dimitrov on Monday.

In other matches on Tuesday, Ryan Sweeting beat American countryman James Blake 6-0, 6-2 in just 45 minutes and wild card Querrey rallied to defeat Alejandro Falla 2-6, 6-3, 6-4.

Sweeting won 75 per cent of his first service points and broke the former world number four Blake three times in each set.