HOUSTON — American Jack Sock defeated former champion Ivo Karlovic 6-1, 6-4 in the first round of the U.S. Men’s Clay Court Championship on Monday.
The 21-year-old Sock had lost both previous meetings with the 2.08-meter Karlovic, who won the only ATP Tour clay-court event in the U.S. in 2007.
Sock broke the eighth-seeded Croatian’s huge serve twice in the first set and won in less than an hour.
Sock’s countryman, Sam Querrey, on the other hand, had to battle to get past Alex Bogomolov Jr., of Russia 6-4, 7-6 (6).
“Right now I’ll take one pretty much however I can get it,” said Querrey, whose ranking has plummeted from a high of No. 17 in 2011 to 82nd.
Querrey, the 2010 runner-up in Houston, hasn’t advanced into the third round of a tournament since the Australian Open in January.
“It’s the first time I’ve been able to grind through a tough match like that all year,” he said. “Hopefully it will lead to more wins and better results.”
Germany’s Dustin Brown beat American Rhyne Williams 6-1, 6-2, while Alejandro Gonzalez of Colombia rallied to eliminate wild card Marcos Baghdatis of Cyprus 4-6, 6-2, 6-1.
Defending champion John Isner, the top seed, received a first-round bye and will play Brown in the second round on Wednesday.