Ramesh Krishnan, rallying from 1-4 down in each of the first two sets, beat Wally Masur, 8-6, 6-4, 6-4, yesterday to give India a 3-2 upset over defending champion Australia in their Davis Cup tennis semifinal.

Earlier, John Fitzgerald defeated veteran Indian captain Vijay Amritraj, 7-5, 6-3, 6-3, to lift Australia into a 2-2 tie.

Krishnan, a superb touch player, proved too consistent for Masur in the 2-hour 5-minute match in Sydney.

India led, 2-0, after Friday's singles, but lost Saturday's doubles as Pat Cash and Peter Doohan defeated Anand Amritraj and Srinivasan Vasudevan, 6-3, 6-4, 6-4. Cash could not play singles because of an injured right knee.

"I am so proud of the Indian team," said Vijay Amritraj, 33, who leads India into the final 18 years after making his Davis Cup debut. "You don't know how much this helps to bring Indians together all round the world. I wouldn't trade today's win for anything I have ever done in tennis."

India became the third nation to defeat Australia in a Davis Cup series on Australian soil. The United States (seven times) and Britain are the other two.

India will face either Sweden or Spain in the final in December. That semifinal was delayed until Monday because of rain in Barcelona. Sweden leads, 2-1 . . .

Unseeded Peter Lundgren of Sweden completed his big weekend by taking just 80 minutes to beat Jim Pugh, 6-1, 7-5, in the final of the Transamerica Open in San Francisco. He earned $44,400 for the victory.

Late Saturday night, Lundgren, No. 49 in the world, fought off two match points to upset top-seeded Ivan Lendl, 6-3, 4-6, 7-6 (10-8), in the semifinals.

Lendl, No. 1 in the world, had not lost a match since the Wimbledon final against Cash three months ago.

Lendl held a match point in the 11th game of the third set and another in the tie breaker . . .

Top-seeded Chris Evert avenged her U.S. Open defeat to Lori McNeil by beating McNeil, 6-3, 7-5, in the women's singles final of the $150,000 Virginia Slims of New Orleans. Evert won $30,500.

McNeil, 23, seeded third, was unable to do much with Evert's precision game and was broken twice in the first set . . .

Top-seeded Martin Jaite battled for 2 hours 47 minutes to defeat Karel Novacek, 7-6 (7-5), 6-7 (9-7), 6-4, to win a clay court Grand Prix tournament in Palermo, Sicily. Jaite got the only service break of the match for either player in the 10th game of the third set for the victory.