Agassi was penalised a point in the third set for cursing twice about line calls. That left him on the verge of ejection, but instead the top- seeded American rallied from a 5-3 deficit thanks to a host of unforced errors by the Ferreira, the fifth seed.
In another quarter-final the Wimbledon finalist MaliVai Washington was eliminated by the unseeded Spaniard, Sergi Bruguera 7-6, 4-6, 7-5. Washington, seeded fourth, served for the match at 5-4 in the third serve but double- faulted on break point and then lost the next seven points.
Britain's Valda Lake and Clare Wood were denied a place in the semi-finals of the women's doubles yesterday when the lost 6-2, 6-1 to the unrelated American pair with the same surname, Mary Joe and Gigi Fernandez.
The Americans, the defending champions and seeded No 1, took charge quickly by winning the first four games. Lake and Wood, who had upset Bulgaria's Maleeva sisters and the seventh-seeded South Africans Mariann de Swardt and Amanda Coetzer, had no answer.
However, Britain are faring better in the men's doubles, where Tim Henman and Neil Broad are just one win away from the first British medal since the sport was re-admitted to the Games eight years ago.
Henman and Broad reached the semi-finals of the men's doubles on Monday by overpowering the fifth-seeded Czechs Jiri Novak and Daniel Vacek 7- 6, 6-4 in 81 minutes.Reuse content