Question: What is the name of this retired professional tennis player and former World No. 1 who was the defending champion of the 2004 Siebel Open - Singles?
Sentence (from "Andre Agassi"): Andre Kirk Agassi ( ; born April 29, 1970) is an American retired professional tennis player and former World No. 1 who was one of the sport's most dominant players from the early 1990s to the mid-2000s.
Relevant evidence: Yes