The Soviet Union handed Cameroon its first-ever World Cup defeat, a 4-0 thrashing in Bari, Italy, last night, but the Africans won Group B and advanced to the second round. The Soviets were eliminated.

Cameroon already had qualified with four points. The Soviets, earning their first two points with this victory, were fourth. Only the top three teams in each group are eligible to advance.

Cameroon lacked the inspired play it showed in upset victories over Argentina and Romania. The Soviet Union dominated from the start and scored twice in each half.

Oleg Protasov and Andrei Zygmantovich beat Cameroon goalie Thomas N'Kono in the first half, while substitute Alexander Zavarov and Igor Dobrovolsky scored after the break.

In the first half Zygmantovich passed to Protasov in the 21st minute for the first Soviet goal of the tournament. It came just after Cameroon midfielder Cyrille Makanaky left the field with an injured leg, putting his side a man down.

The goal put Cameroon, which had three ties in the 1982 World Cup, behind for the first time in the tournament.

Zygmantovich scored 11 minutes later after Sergei Aleinikov moved in alone from the left, dribbled past N'Kono and put a shot off the crossbar. The Soviet midfielder dived to drive home the rebound.

Zavarov scored on a long run from the left side in the 53rd minute. He fended off the challenge of defender Bertin Ebwelle and fired a left-footed drive that deflected off N'Kono. Ten minutes later Dobrovolsky headed in a long pass.

Cameroon 0 0 0 Soviet Union 2 2 4 FIRST HALF Scoring: 1, Soviet Union, Protasov 1 (Zygmantovich), 21st minute. 2, Soviet Union, Zygmantovich 1 (Aleinikov), 32nd minute. SECOND HALF Scoring: 3, Soviet Union, Zavarov 1, 53rd minute. 4, Soviet Union, Dobrovolsky 1 (Aleinikov), 63rd minute. Yellow Cards: Kana Biyik, Cam, 61st minute; Milla, 66th minute; Protasov, 75th minute. Red Cards: None. Referee: Wright (Brazil). Linesmen: Roethlisberger (Switzerland); D'Elia (Italy). A: 37,307.

Argentina 1, Romania 1:

In Naples, Italy, the teams settled for a tie -- and berths in the second round.

Romania, second in Group B with three points and a 4-3 goal differential, made it past the first round for the first time in five World Cup appearances. It will play the second-place team in Group F.

Argentina, third in Group B with a 3-2 goal differential, likely will face either West Germany or Brazil.

Defender Pedro Monzon's header put Argentina ahead in the 61st minute after a corner kick by Diego Maradona. But Gavril Balint tied it in the 69th minute and the teams played cautiously the rest of the way.

On the tying goal Marius Lacatus passed to the far post and the ball was headed back across the goal by Ioan Sabau. Balint put it home.

Maradona was treated roughly by the Romanians, and Lacatus and Gheorghe Hagi drew yellow cards for overly vigorous tackles on Maradona.

Lacatus also made an impact on attack, firing just wide, then having his hard shot stopped on a diving save by Sergio Goycoechea in the 26th minute.

Romania 0 1 1 Argentina 0 1 1 FIRST HALF Scoring: None. SECOND HALF Scoring: 1, Argentina, Monzon 1 (Maradona), 61st minute. 2, Romania, Balint 2 (Sabau), 69th minute. Yellow Cards: Lacatus, Rom, 4th minute; Hagi, Rom, 8th minute; Lupescu, Rom, 32nd minute; Serrizuela, Arg, 86th minute; Batista, Arg, 86th minute. Red Cards: None.Referee: Silva Valente (Portugal). Linesmen: Perez Hoyos (Colombia); Longhi (Italy)A: 52,733.