Milos Raonic was a Tuesday winner, while defending champion Alexandr Dolgopolov was an upset victim during second-round action at the $1.3 million Citi Open tennis event.
Indian qualifier Somdev Devvarman toppled the ninth-seeded Dolgopolov in 6-3, 7-6 (7-4) fashion on the hardcourts at FitzGerald Tennis Center. The Ukrainian Dolgopolov beat German star Tommy Haas in last year's D.C. finale.
Raonic, the Canadian four seed, breezed past Aussie Samuel Groth in a 71- minute, straight-set triumph. His next opponent will be Australian surprise Marinko Matosevic, who knocked off 15-seed Nikolay Davydenko, 6-4, 7-5.
American Sam Querrey needed almost two hours to win his match against Denis Istomin, but eventually did so by a 6-4, 3-6, 7-6 (11-9) count.
Marcos Baghdatis, the 16th seed and runner-up here in 2010, won his second- round match against Lukas Lacko, 6-7 (2-7), 6-2, 6-4.
Other second-round winners in America's capital were Bernard Tomic, who took down David Goffin 6-1, 6-3; Grigor Dmitrov over Xavier Malisse 7-6 (7-4), 6-4...
In opening-round action involving Americans on Day 2, qualifier Alex Kuznetsov doused Russian Alex Bogomolov 6-3, 4-6, 6-3 and wild card Jack Sock whipped Dutchman Igor Sijsling 6-4, 6-2. Ryan Harrison was taken down by Australian Lleyton Hewitt in straight sets. The former world No. 1 Hewitt titled here in 2004, but moved into 2013's second round with a 6-3, 7-5 decision.
Other first-round winners from the rest of the world included James Duckworth, who topped Yuichi Sugita 6-2, 6-2 and Russian Dmitry Tursunov posting a 7-6 (7-5), 7-5 triumph over Canadian Jesse Levine.
The 2013 Citi Open champ will collect $292,200.