Black Knocks Rios From the Top Spot

Byron Black of Zimbabwe ended the run of Marcelo Rios as the world’s top-ranked tennis player by beating the Chilean, 5-7, 6-1, 7-5, in the third round of the RCA Championships on Thursday night.

Rios needed to reach the semifinals to remain ahead of Pete Sampras, who was upset earlier Thursday at the Pilot Pen International in New Haven, Conn.

“It’s really difficult for me to play at night,” Rios said. “I hit too many unforced errors.”

Andre Agassi struggled but reached the quarterfinals by beating Wayne Black, Byron’s brother, 7-6 (7-4), 3-6, 6-1. Agassi will meet South Africa’s Wayne Ferreira, who also struggled before turning away Australia’s Jason Stoltenberg, 3-6, 7-5, 7-6 (12-10).