Chang was one of the few remaining seeded players left after the top seed and defending champion Pete Sampras led six players out of the tournament on Wednesday.
In the only battle among seeded players in the third round, French Open champion Yevgeny Kafelnikov, the No 4, defeated MaliVai Washington, the No 13, 6-4 6-3.Wayne Ferreira had become the 10th seed to go out when he lost 6-2, 6-4 to Sweden's Magnus Gustafsson.
The result means that Boris Becker, beaten by Spain's Carlos Moya in the second round on Wednesday, is assured of his place in the eight-man ATP Tour World Championship in Hanover next month, where he will defend the title.
Pete Sampras, Michael Chang, Goran Ivanisevic, Yevgeny Kafelnikov, Thomas Muster and Agassi have already gained a spot for the end-of-year event, which starts on 19 November. Agassi's place was confirmed after the Wimbledon champion, Richard Krajicek, withdrew from next week's Stockholm event.
Stefan Edberg rallied to beat the Dutch qualifier Fernon Wibier 4-6, 6-4, 6-2. The Swede won 10 of the last 13 games.