Published: Feb. 20, 2013 at 1:01 AM
MEMPHIS, Feb. 20 (UPI) -- Fourth-seeded Sam Querrey upended Alejandro Falla Tuesday in the opening round of the U.S. National Indoor Tennis Championships in Memphis.
Querrey won 52 percent of his return points and ousted Falla in 58 minutes.
Kei Nishikori, the No. 5 seed, also moved on with 6-4, 7-5 win over qualifier Illya Marchenko, and Igor Sijsling topped defending champion Jurgen Melzer 6-4, 7-6 (3).
James Blake beat Florian Mayer 4-6, 6-3, 6-2.
Third-seeded John Isner was knocked off by Denis Istomin 6-4, 6-3. Istomin won 86 percent of his service points in the victory.