NEW DELHI, India (AP) _ Brothers Vijay and Anand Amritraj defeated a Soviet team in doubles Saturday, giving India an unbeatable 3-0 lead in their Davis Cup tennis competition against the Soviet Union.

India, by winning the best-of-five match, will stay in the elite World Group of Davis Cup competion for one more year. The Soviet Union dropped back to zonal play for next year.

The Amritraj brothers took five sets to beat Alexander Zverev and Sergei Leonyuk 2-6, 6-3, 6-2, 1-6, 6-4, the United News of India reported.

On the first day of play Friday at New Delhi's new 3,500-seat tennis complex, Vijay Amritraj handily downed the No. 1 Soviet player Andrei Chesnokov 6-1, 6-4, 6-4.

Ramesh Krishnan, a quarterfinalist at this year's Wimbledon, had to come from behind to capture his match Friday against Zverev, winning 3-6, 3-6, 6-0, 6-1, 6-4.

The contest is being played on grass courts, which the Indian players are more accustomed to than the Soviets.

Sunday's ''reverse singles'' will pit Krishnan against Chesnokov and Vijay Amritraj against Zverev.