Zina Garrison and Gigi Fernandez broke Jana Novotna's serve in the ninth game of the second set yesterday, opening the way for the United States to take a 7-6 (10-8), 6-4 victory over Czechoslovakia in a quarterfinal match of the Federation Cup in Norcross, Ga.

The top-seeded U.S. team meets No. 3 Austria, which defeated Britain, 2-1, in one of Saturday's semifinals.

The Americans needed to win the doubles because Garrison lost her singles match to Novotna, 6-3, 6-3.

"She was everywhere I hit the ball," Garrison said. "When I thought I hit a good serve, she would hit an even better return."

The Czechoslovak team was hurt by the loss of injured Helena Sukova, its No. 1 player who usually pairs with Novotna to form the No. 1 women's doubles team in the world.

Jennifer Capriati fell behind by 2-5 in the second set but bounced back to defeat Regina Rajchrtova, 6-2, 7-6 (7-4), in the opening match.

In today's other quarterfinals, No. 2 Spain meets No. 5 France and the Soviet Union takes on the Netherlands.

Canadian Open: Top-seeded Andre Agassi beat Darren Cahill, 6-2, 6-4, in Toronto to move into the quarterfinals vs. Michael Chang.

Third-seeded John McEnroe, a two-time champion, defeated Amos Mansdorf, 6-3, 6-4. McEnroe will meet rising American Pete Sampras, 18, for the first time. Sampras was a 4-6, 6-3, 6-2 winner over Andrew Sznajder.

Seventh-seeded Chang ousted No. 9 David Wheaton, 6-0, 6-3, to set up a rematch of this year's French Open and Sovran Bank Classic semifinals, both won by Agassi, who is 4-0 against Chang.

Jakob Hlasek ousted Jimmy Arias, 7-5, 6-1, and next meets Todd Witsken, who eliminated Ramesh Krishnan, 6-4, 6-4. No. 6 Tim Mayotte beat Richey Reneberg, 6-3, 4-6, 6-3, and faces No. 4 Jay Berger, who defeated Derrick Rostagno, 4-6, 6-4, 6-1.