John Atta Mills spoke to the players in the dressing room, giving them a pep talk before they prayed together, Ghana Football Association vice-president Fred Pappoe told Reuters.
"It made a lot of difference to the boys," said Pappoe, who is also head of management for the Black Stars. "We always pray - before a game, in the bus, in the hotel and also on the pitch before each half and afterwards, no matter what the result.
"But to have our president here and sitting in the stands next to (FIFA president) Sepp Blatter was a solid morale-booster for the team. When he came to the dressing room, to see the boys, and to pep them up, it meant a lot.
"He said some prayers with the team, a special word of prayer just before the game when they went on to the pitch and it made a difference."
Ghana, who face Uruguay in the quarter-finals at Soccer City in Johannesburg on Friday, are the only African team still in the tournament following the group stage exits of hosts South Africa, Nigeria, Algeria, Cameroon and Ivory Coast.
EMOTIONAL WIN
Their emotional extra-time win at the Royal Bafokeng stadium sparked wild celebrations as the players ran round the field with the South African and Ghanaian flags amid a riot of vuvuzela-led noise.
Pappoe said the Ghana players were all fully aware of their extra responsibility now they were seen as representing the African continent.
"It means a lot but it brings a lot of pressure and expectation and, of course, it would be lighter for them if there were one or two other African countries still in the competition.
"But we take this in our stride and our boys are playing to do their best and to reach their limits. We are the only team holding high the flag of Africa now so it is a moment of great pride for us, but we take it also in all humility."
He added that the president's visit had helped calm the players' nerves. "They were, surprisingly, not nervous at all because they have faith in the coach and believe that if they play by the rules all will be fine," he said.
"We take one game at a time and now go to the drawing board again and look at Uruguay to examine the mentality and resilience of that team. And, with the great support of Africa, I am sure we can go beyond them to the semi-finals."
