Cameroon went down fighting - off the ball and amongst themselves - as they exited the World Cup on Wednesday with Alex Song adding a red card to the ill-disciplined African nation's long list in a thumping 4-0 defeat by Croatia.

The Europeans were already leading 1-0 when Barcelona midfielder Song opted for a petulant elbow smash into the back of Croatian striker Mario Mandzukic in the 40th minute of their Group A clash in Manaus.

Cameroon's Achille Weboc tries to separate teammates Benjamin Moukandjo and Benoit Assou-Ekotto. Credit:Reuters

As Mandzukic collapsed in agony, Portuguese referee Pedro Proenca swiftly dismissed Song - the eighth red card for Cameroon in seven World Cup finals appearances.

There was further unruly behaviour in the closing stages of the game when fullback Benoit Assou-Ekotto and teammate Benjamin Moukandjo had to be separated after rutting heads.