Calvin Smith's unbelievable anchor leg carried the United States men to a meet-record victory in the 4x100-meter relay tonight at the 18th U.S.-U.S,S.R. dual track and field meet.

Smith's remarkable come-from-behind triumph, over an amazed Soviet anchorman who was signaling apparent success, and an American-record time in the women's version took some of the sting out of a disappointing night that saw the U.S. fall behind in the point scores for both sexes.

The Soviet men, although winning only four of 10 events, took a 54-50 lead on a 5-3-2-1 basis, with relay scoring 5-2. The Soviet women, winning four of eight, took a 45-39 advantage.

The only U.S. sweeps came in the 100 meters, both in meet-record time despite a moderate headwind. Carl Lewis nipped Smith with a late lean in 10.09 seconds and Evelyn Ashford breezed home ahead of Florence Griffith in 11.18.

An apparent American one-two finish in the men's 400 meters was nullified, when runner-up Tony Darden was disqualified for taking six steps on the lane line around the final turn. Darrell Robinson, the high-school kid from Tacoma, Wash., won the event in 45.36.

The Soviets were hit by an apparent disqualification, too. Nina Yepeyeva, second to teammate Tatyana Pozdonyakova in the 3,000 meters, was bounced for cutting off American Jan Merrill on the final straightaway.

Long after the meet ended, the jury of appeals, with Primo Nebiolo of Italy, the IAAF president, casting the deciding vote, overruled the games committee and reinstated Yepeyeva. At the same time, the jury accepted a Soviet protest involving the triple jump that moved American Paul Jordan from third place to fourth.

Dave Laut added almost two feet to the meet record in the shot put when he heaved the ball to a personal best of 71-5 1/2 on his final try. A sixth meet standard fell in the new Indiana University Track Stadium when Soviet Irina Baskakova took the 400 meters in 50.78.

The heralded pole vault came apart early, as home-state hero Dave Volz, who set an American record of 18-9 1/2 last week, failed in three tries at 17-9 1/4 and did not score. Billy Olson won the event at 18-3 1/4, but elected not to try to regain his American mark because of a slight hip strain and rain.

The 8,185 fans saved most of their cheers for Smith and Doug Padilla, who fought off Valeri Chumakov down the stretch to capture the 5,000 meters in 13:33.34.

In the relay, there were hopes of beating the world record of 38.03. They vanished when third-place Darwin Cook, the H.D. Woodson graduate, found Smith an elusive target for his handoff. When Smith finally took the baton, he was virtually standing still and looking at a five-meter deficit behind Aleksandr Sidorov's disappearing jersey.

In open sprints, Smith usually is a fast starter whose finish is a problem, and earlier he had moved into a clear advantage over Lewis in the 100, only to be nailed at the tape. This time, however, the speedy Alabama junior moved into high gear himself, eating up most of the space over the last 50 meters, when he had reached full speed.

At the finish, Sidorov signaled victory, then fell.

Terron Wright and Mike Miller ran the first two legs for the U.S. team, timed in 38.54. The losing Soviets matched the old meet mark of 38.56 established by a U.S. quartet at College Park, Md., in 1976.

The U.S.'s Alice Brown, Florence Griffith, Randy Givens and Diane Williams leaped in joy after their 42.47, which beat the American record (42.82) and the Soviets' 42.93 meet standard at College Park.