O-KEI

Japanese teen star Kei Nishikori won his 10th straight ATP Tour match Wednesday, beating Argentina’s Diego Hartfield 7-5, 6-3 to advance to the second round of the SAP Open.

The 18-year-old Nishikori, 131st in the world rankings following his victory over James Blake on Sunday in Delray Beach, Fla., will face top-seeded Andy Roddick, a 6-3, 6-7 (3), 7-6 (5) winner over Chris Guccione.

Nishikori, the first Japanese player to win an ATP Tour title since Shuzo Matsuoka in Seoul in 1992, was looking forward to a match against Roddick who was in the stands.

“I think I’m ready,” Nishikori said. “I’ll be facing another top 10 player. His serve is a big thing. He’ll be the highest ranked player I’ve ever played.”