MEMPHIS, Tenn. (AP) — Jack Sock of the United States upset No. 2 seed Milos Raonic in opening-round play with a 6-3, 5-7, 7-5 victory Wednesday at the U.S. National Indoor Tennis Championships.
Raonic, who won the title at the SAP Open in San Jose last week, had finished as runner-up to Andy Roddick in 2011 and to Jurgen Melzer in 2012.
Sock won his first tour match of the year.
"It's always nice to get the highest-ranked win of my career," Sock said. "And it was nice to get that first win of my career. I hope to carry the momentum on this week."
Sock broke Raonic to go ahead 6-5 in the final set and closed the match with an ace, his 11th of the match.
Other seeds advancing Wednesday were No. 6 Tommy Haas of Germany and No. 7 Alexandr Dolgopolov of Ukraine.
Haas, runner-up to Raonic last week, posted a 7-6 (6), 6-4 victory Wednesday over Russia's Evgeny Donskoy.
Haas, 34, the oldest player in the draw, is a three-time Memphis champion who won the first ATP Tour title of his career in Memphis 14 years ago.
In other first-round play, former world No. 1 Lleyton Hewitt of Australia survived two match points in the second set and defeated Yen-Hsun Lu of Taiwan 2-6, 7-6 (3), 6-4.
Hewitt, who turns 32 Sunday, is seeking his first Tour title since 2010.