Senegal's attacking talisman was ruled out of the World Cup on Thursday after injuring his knee playing in the Bundesliga 10 days ago in a major blow to his country's hopes.
But Ake said it will not diminish the threat they will face at the Al Thumama Stadium on Monday.
"It's going to be very tough," he told a news conference.
"Senegal has good players and very strong strikers, even without Mane. Missing the World Cup due to an injury is very annoying, not only for him.
"Everyone wants to see the top players at work here. The fact that Mane is not there is therefore a loss for this World Cup," he said, echoing what captain Virgil van Dijk (31) had said earlier.
"But we still have to prepare for a very tough job, because Senegal remains very strong. We’ve analysed them well."
Ake has bedded down a place in the Dutch back four over the last few months. "I hope I can play on Monday but we have many top defenders to pick from," he said.
But with coach Louis van Gaal expected to play three centre backs, the Manchester City player believed his chances of lining up against Senegal were good.
