The Black Stars finished second in Group D following a 1-0 reversal to Egypt in their last game on Wednesday, booking a last eight meeting with Group C leaders DR Congo.
Ghana were, however, dealt a blow in the first half following a suspected groin injury to Gyan.
"The two teams [DR Congo and Morocco] that qualified from Group C are good and it's going to be a tough game anyway," Grant said.
"I hope the pitch in Oyem [for the quarter-final clash] is better. I would have liked to win but now we have to focus on the quarter final.
"It was a game decided by one mistake. They scored from a fantastic free-kick but we dominated after that.
"Unfortunately we didn't score, but I'm happy with my players' attitude. This is football.
"On Sunday, it is a different story and it would be a tough game.
"Asamoah Gyan injury is not looking good but we will see what happens and I hope he will be better.
"We will have a scan & then we will know better.”
AS Roma winger Mohamed Salah scored the only goal of the match from a free-kick on 11 minutes after Abdallah El-Said was fouled by John Boye.
Ghana have already been reduced by a man at the Afcon following injury to Baba Rahman in the group opener against Uganda.
The Schalke 04 defender has since flown back to Europe and medical diagnoses say he faces up to seven months on the sidelines.
Ghana play DR Congo on Sunday.