Kwesi Appiah's men were unfortunate not to take all three points from an enthralling 2-2 draw with Germany on Saturday.
Afful played a key role in that game, supplying the cross for Andre Ayew to cancel out Mario Gotze's second-half opener, before Asamoah Gyan completed an unexpected turnaround.
But there was a final twist in the tale as Germany substitute Miroslav Klose rescued a point for Joachim Low's side by scoring the 15th World Cup goal of his career, tying Brazil great Ronaldo for the most in the history of the competition.
Ghana can still qualify despite the draw, although a United States victory over Portugal on Sunday would all but eliminate them from the competition. However, regardless of the permutations, Afful is adamant Ghana will fight to the end.
"It's a shame we couldn't win. It would have been great to take all three points," Afful told FIFA.com.
"But we ran ourselves into the ground and played really well against a team of the calibre of Germany.
"We've still got a game to go and we're going to give it our all to go through.
"If we don't qualify, it won't be for lack of effort."
Ghana's final group game with Portugal takes place in Brasilia on Thursday.
