Sixth seed Steve Johnson was given a work out as he made it through to the second round of the BB&T Atlanta Open on Tuesday.
It took Johnson just shy of two hours to see off the unseeded Slovak Lukas Lacko 6-1 6-7 (3/7) 6-2 as he hit 15 aces.
The two other seeds in action on Tuesday also made it through as fifth seed Marcos Baghdatis beat qualifier Austin Krajicek 6-4 6-0, while eighth seed Benjamim Becker advanced after his fellow German Michael Berrer retired hurt - although Becker had taken the first set 7-5.
Qualifier Denis Kudal saw off wildcard Ryan Harrison 3-6 6-4 7-6 (7/5), Jared Donaldson beat Somdev Devvarman 6-1 3-6 6-4, and Sam Groth dispatched wild card Frances Tiafoe 7-6 (7/3) 6-4.
Source: PA