It was going to take something special to break the deadlock and the Rennes striker did just that with a classic goal in the 93rd minute to send Ghana, the last remaining African side in the global showpiece, into the quarterfinals.
The Black Stars will meet Uruguay at Soccer City in the quarterfinals next Friday at 8.30pm .
Among the celebrities in the 34 976 strong crowd at the Royal Bafokeng Stadium were Rolling Stones legend Mick Jagger who sat next to former USA president Bill Clinton.
Ghana impressed in the opening period and showed more flair, skill and initiative and on the run of play deserved their 1-0 lead at the interval.
But the Black Stars lost the plot in the second half and fell apart.
Ghana can thank goalkeeper Richard Kingson for keeping them in the game after the break against a determined US side that finally found their feet and were able to take the game away from the West Africans in the second period.
The Black Stars got off to a flying start in the fifth minute when their Portsmouth striker Kevin Prince Boateng weaved and jinxed his way through a cluster of ruffled American defenders and planted the ball past Tim Howard in the United States goal to put Ghana 1-0 ahead with a brilliantly taken goal.
The stunned US side struggled to get their rhythm back. Jozy Altidore shot wide of the Ghana goal in the 12th minute as America tried to regroup from the early setback.
But it was Ghana who kept up the pressure. Howard did well to punch away a powerfully struck free kick from Gyan in the 18th minute.
US German based midfielder Michael Bradley tested Kingson with a shot at the near post in the 22nd minute as the US battled to get into the game.
US coach Bob Bradley pushed the panic button in the 31st minute when he replaced Richard Clark, the Eintracht Frankfurt midfielder with Glasgow Rangers Maurice Edu to add more punch into the misfiring American engineroom.
The US were denied an equaliser in the 35th minute by a superb save from Kingson. The Black Stars keeper, who plays in the English Premiership with Wigan, did well to come off his line and block a goal-bound shot from Robbie Findlay.
Two minutes later it was Howard’s turn to keep his side in the game with a good save from close range from Kwando Asamoah.
A clever substitution at the start of the second half by coach Bradley almost paid dividends. The US coach brought Norway based midfielder Benny Feilhaber on in place of Findlay who had a quiet first 45 minutes.
Feilhaber nearly made the difference with his first touch but was thwarted by another fine save from close range by Kingson in the 47th minute.
The US were a lot more positive in the second half. It took a strong and well timed challenge from Ghana captain John Mensah to stop Clint Dempsey getting in a shot on goal in the 54th minute.
Mensah who plays for Sunderland did well to take the ball from Fulham’s Dempsey on the edge of the area as the US midfielder was racing in on goal.
But Ghana struggled to contain the rejuvenated Dempsey and paid the penalty in the 61st minute when Free State Stars defender Jonathan Mensah tripped Dempsey inside the danger area and Hungarian referee Viktor Kassai had no hesitation in pointing to the penalty spot.
US talisman Landon Donovan, who scored the last gasp winner in the final group stage clash against Algeria to earn his side a 1-0 win and place in the Last 16, took the responsibility and slotted home a well drilled penalty to level the tie.
Kingson came the rescue again in the 67th minute when he rushed off his line and beat the on-rushing Altidore to the ball to prevent the American striker giving his side the lead.
Kingson was the busier of the two keepers in the second half and did well again in the 76th minute to stop Bradley giving the US side the lead with a fine save.
Altidore was unlucky four minutes later when he bustled his way past the Ghana defence only to see his shot skim past the upright.
But with neither side managing to get the breakthrough the match went into extra time.
The killer blow came three minutes into extra time when Gyan beat off a determined challenge from US defenders Carlos Bocanegra and Jay DeMerit to volley home a sensational winner. However, the Ghanaians survived a nail biting last two minutes where US piled on the pressure and substitute Heculez Gomes’ shot was defected for a corner.
But Ghana held on to book their place in the quarterfinals.
United States: Tim Howard, Steve Cherundolo, Carlos Bocanegra, Jay DeMerit, Jonathan Bornstein, Landon Donovan, Michael Bradley, Ricardo Clark (Maurice Edu, 31), Clint Dempsey, Jozy Altidore (Herculez Gomez, 90), Robbie Findley (Benny Feilhaber, 46).
Ghana: Richard Kingson, Hans Sarpei (Lee Addy, 73), Asamoah Gyan, John Pantsil, John Mensah, Anthony Annan, Samuel Inkoom (Sulley Muntari, 113), Jonathan Mensah, Dede Ayew, Kwadwo Asamoah, Kevin-Prince Boateng (Stephen Appiah, 78). AP