NORCROSS, Ga. (AP) -- Qualifiers Rajeev Ram and Marinko Matosevic upset seeded opponents in the first round of the Atlanta Tennis Championships on Tuesday.
Ram, who won 32 of 35 first-serve points, knocked off 20-year-old Grigor Dimitrov of Bulgaria, the No. 5 seed, 6-4, 6-4.
Australia's Matosevic closed his 6-7 (3), 6-2, 7-5 win over No. 6 seed Igor Kunitsyn of Russia with two aces.
In other matches, Lleyton Hewitt of Australia ignored recurring pain in his foot to beat Phillip Simmonds 6-4, 6-4, Yen-Hsun Lu of Taiwan held off Matthias Bachinger of Germany 7-5, 7-6 (4), and Ryan Harrison took a 6-1, 7-6 (5) victory after Japan's Yuichi Sugita won only five of 39 first-return points.
Nicolas Mahut of France saved four of six break points in a 7-6 (5), 6-2 win over Richard Berankis of Lithuania.