Mohammad Ali, who yesterday met Leonid I. Brezhnev and got kissed, tonight went into the ring with some Soviet boxers and almost got pasted.

Going two rounds apiece with three separate Soviet champions, Ali was slow, fat and winded, the dignity of his ceremonial visit to this country's president brushed away by the agressive attacks of men much younger, much fitter.

He marked it one win, one loss, one draw after the scoreless exhibition match at the Central Army Sports Club in Moscow that drew thousands and created at the gates a traditional shouting, sweating, fearsome crowd of Russians desperate to get inside for a look at the capitalist professional boxer world's most remarkable figure.

The first two-round match with Pyotr Zayev, a compact heavyweight who has held the Soviet all-round championship, was the worst. Ali stumped backward on heavy legs while Zayev hunted, threw combinations, bobbed away from awkward counters and then plowed in again.

"He was the best all-round boxer," Ali said later of Zayev, 26. The former world champion lost both rounds as the heavily Russian crowd, which had given him a rousing ovation when he appeared in the arena, whistled and shouted prodding insults. Once Ali took a right to the chin and the crowd raored. They roared again with delight when Ali faked a punch at the referee who was warning him about holding.

But by the end of the second round, Ali, at 234 pounds with packed fat around his waist and thighs, was taking his time in the clinches and sitting heavily on his stool between rounds.

The second fighter was Evgeny Gorstkov, 28, a three-time all-round Soviet champion. Ali straightened Gorstkov with some jabs to the head, cut him on the face and won the brief contest with some flurries at the end of both rounds.

"The second guy was awkward. He wouldn't get anything," Ali said later.

By far the most interesting match was with Igor Vysotsky, the Soviet heavyweight champion. The two had sparred two amusing, one-minute rounds a week ago at the Central Sports Institute, when Ali stripped to the bottom half of the blue pinstripe diplomatic suit and gone into the ring.

Vysotsky, a 24-year-old with the splayed nose and scarred brows and ears of a fighter who wades straight in, did so in the first round. Ali held him off, taking the flurries mostly on his hands and arms but losing the round.

In the second, the 36-year-old former champion reached the current Soviet champion with three long lefts to the face and three smoking flurries out of clinches on the ropes that brought the crowd alive. Vysotsky lost some blood and the round. If they had been using the six-ounce gloves of professionals instead of the 10-ounce gloves of amateurs, he might have lost his feet.

"It could have been a draw," Ali estimated afterwards.

"I done my best, but I was not at my best," the fighter said later as he sprawled in his shorts on an uncomfortable easy chair in his dressing room, next to a plug-in samovar and unused Russian tea glasses in their metal holders.

"I wish I was 28. Let me come back here and let each guy be 36," he said defensive and wistful. "Everyone suprised me. They were hard to hit and they hit hard and were just aggravatinb."

He enumerated. "I've had 119 amateur fights, 55 professional fights, and boxed maybe 10.000 rounds. I've run maybe 5,000 miles, done the speed bag, the rope, with worries and troubles. I'm a human miracle to be getting into the ring. Getting ready for Spinks is gonna be hell."

He is scheduled to fight Leon Spinks in September. The 24-year-old former Marine and Olympic champion took Ali's crown in February in a 15-round fight that seemed to have finally opened the door to retirement from thr ring for this charismatic man.

But Ali says he will be "the first man in history to win the title three times." He has a long uphill climb to that feat, gauging by his excess weight, slowness and lack of wind tonight.

And he knows it. "I'm finished," he said. "I fought tonight on guts, courage and native ability. My bones are hurtin', the weight's hard to come off, timing's off, I get hit too easy. I've been fighting for 25 years."

What the future holds is unclear. He would like to be a kind of international goodwill ambassador, and was called by Brezhnev an "unofficial ambassador for peace" to America. But that is a rocky road for a man who has spent his energy in a prize ring. Ali found some of those rocks earlier today when he met several hundred resident Americans at the U.S. embassy. There, among the diplomats, military attaches, Marines in their off-duty "Trouble, Inc, - Moscow Marines" t-shirts, his amiable homilies about the goodness of life in the Soviet Union and his impressions of its peace-loving people fell on stony ground. The crowd warmed only when he talked prize-fighting.

Tonight, taping his hands before the exhibition, a ritual he has undergone probably thousands of times, he fell into a monologue on his situation, a paean to himself and a rumination of the damning passage of time that leaves him with fame and fleeting skills. It was an elegy refracted through the lens of his visit here, when a black prizefighter was accorded the true esteem of being worthy of a visit with Brezhnev, leader of a secretive leadership contesting for world supremacy with Ali's native country.

"You all watching the end of the greatest fighter of all times. You know how times goes by and you don't even notice it. I remember the '60 Olympics and realize what a beautiful time it was. You look back on the day and you realize how good it was . . ."

He was Cassius Marcellus Clay then, a kid from Louisville, Ky., who won the heavyweight championship and went on to win much more. It isn't over, but Ali, poised on the edge of end, knows how wonderful it all was. It is a bittersweet revelation.