Asamoah Gyan kept the African flag flying at the World Cup with a superb left-foot strike in extra-time as Ghana overcame the United States 2-1 to reach their first quarter-final.

It was the second time in successive World Cups that Ghana had defeated the United States, having effectively dumped them out of the tournament four years ago by beating them in the final group game.

Gyan's goal, after 93 minutes, was worthy of winning any game after he outmuscled USA captain Carlos Bocanegra to blast his shot past goalkeeper Tim Howard. It settled a contest that was level at full-time after Landon Donovan's second-half penalty cancelled out a fifth-minute strike from Kevin-Prince Boateng.