Updated

Johns Creek, Georgia (SportsNetwork.com) - Sixth seed Denis Istomin, eighth seed Marinko Matosevic and American Jack Sock were a trio of easy first-round winners Tuesday at the Atlanta Open tennis event.

Uzbekistan's Istomin eliminated American lucky loser Rajeev Ram 6-1, 6-4, while the Australian Matosevic blew past Dominican Victor Estrella Burgos 6-0, 6-2 in a mere 43 minutes and Sock vanquished Colombian Alejandro Gonzalez 6-2, 6-4 on the hardcourts at Atlantic Station. Sock's second-round opponent will be qualifier Michael Venus of New Zealand.

An all-American affair saw Tim Smyczek drill wild card Ryan Harrison 6-0, 6-2, while another American landed in the win column when wild card Robby Ginepri outlasted Ukrainian Sergiy Stakhovsky 7-6 (7-3), 3-6, 6-0.

Additional wins came for Dutch lucky loser Thiemo de Bakker, German Benjamin Becker, Slovakian Lukas Lacko and Ukrainian qualifier Illya Marchenko.

The top seed in Atlanta is 6-foot-10 American, reigning champion and two- time runner-up John Isner, who beat 6-foot-8 South African Kevin Anderson in last year's all-tall finale. Isner will open up against his compatriot Ginepri this week.

The 2014 Atlanta champ will claim $103,000.