Steffi Graf, given a free ride into the final when Chris Evert took ill, shoots for the biggest prize in tennis Saturday when she plays Gabriela Sabatini for the U.S. Open Championship.

One more victory, added to the 59 she has accumulated this year, would allow Graf to become the third woman ever to win the Grand Slam, and the first since Margaret Smith Court in 1970.The 19-year-old West German, winner of her last 33 matches, was in her hotel room Friday morning when she heard on television of Evert's illness, and she expressed disappointment the match was off.

"It would have been important for me to play against Chris," Graf said, alluding to the fact she has yet to be tested in the Open, dropping merely 13 games in five victories. "She has the kind of game which gives me a harder time."

All that remains now in Graf's path is Sabatini, her doubles partner and the only woman to defeat her since Graf lost to Martina Navratilova in the Open final one year ago. Sabatini became the first Argentinian woman ever to gain a berth in a Grand Slam final Saturday when she beat Zina Garrison, 6-4, 7-5.

This will be the first women's final at Flushing Meadow since 1974 in which either Evert or Navratilova is not playing.

Ivan Lendl, the men's top seed, and Andre Agassi, rated fourth, will meet in the semifinals Saturday. Mats Wilander, the No. 2 seed who is seeking his third Grand Slam crown this year, plays unseeded Darren Cahill of Australia in the other match. The winners meet Sunday.

In an incredibly strange sequence of events Friday, first Evert and then Rick Leach, scheduled to play in the men's doubles final, defaulted because of a stomach virus. This wiped out two of the three matches scheduled for the Stadium Court.

According to Dr. Gary Wadler, the tournament physician, Leach was taken to North Shore University Hospital. Evert was resting at her hotel.

"I was really looking forward to playing Steffi and being part of her Grand Slam bid," Evert said in a prepared statement. "I could have gone out there with no pressure, hit out and really have given it a shot against Steffi. It's the first time in 18 years of Grand Slams that I've had to default.

"My body feels like it's been through a war. Every muscle and joint aches. Physically, I couldn't go out and play. I don't have any energy."

Wadler said Evert had a temperature of 101 degrees and Leach of 103 degrees. He said both had similar symptoms of vomiting, diarrhea, muscle aches, fever and nausea.

This was the first time since 1902 that anyone had withdrawn from a singles semifinal at the National Championships.

The withdrawal of Leach and Jim Pugh allowed Spaniards Emilio Sanchez and Sergio Casal to win the men's doubles.

As a result of the sick calls, the only match played early in the day received less attention.

Sabatini, who has handed Graf her only two losses this year, the last one in April, used a destructive backhand topspin to keep Garrison pinned beyond the baseline.

Garrison, who ended a 21-match losing streak to Navratilova by upsetting the defending champion Wednesday, jumped to a 2-0 lead, but Sabatini rallied to win the next four games.

After Garrison held to close to within 4-3, the key game came in the eighth when Garrison got to triple break point, but the 18-year-old Argentinian was able to hold with a service winner.