Unbeaten Muhammad Ali came alive in the waning minutes of the 15th round and stopped crude but, strong Oscar Bonavena on three knockdowns in an amazing finish at Madison Square Garden Monday night.

Weary and desperately trying to hold off the bull-like rushes and lunges of the South American heavyweight champion from Argentina, Ali suddenly nailed the strong-jawed Bonavena with a solid left hook to the jaw that dropped Oscar for a count of six.

The capacity crowd in the Garden roared as Ali followed with a sharp right left combination to the jaw which again felled the gutty Bonavena for a count of four. As he was getting the mandatory eight-count, Bonavena's corner tossed a towel into mid-ring.

But Ali unloaded another left and right that felled the South American again.

This immediately ended the fight under the three-knockdown rule at 2:03 of the final round. The fight had been astonishingly close until Ali's sudden thunder brought it to a wild end.