Salah had missed the opening 1-0 loss to Uruguay as he struggled to recover from the shoulder injury that curtailed his involvement in the Champions League final at the end of May.
Although he started against Russia and converted a consolation penalty, Salah looked far from 100 per cent fit and cut a dejected figure at the final whistle, but Mane says his Anfield colleague is strong enough to recover from the disappointment.
"Unfortunately, he arrived suffering from injury and I was wishing him the best but he's a very strong guy mentally.
"He did fight hard, he came back to help his country. Unfortunately they struggled but it's football, you have to live with it.
"I wish him all the best for the future and at the moment of course it's normal for him to have difficulties, that's football."
Mane will come up against former Southampton team-mate Maya Yoshida in Ekaterinburg on Sunday and revealed how the Japan defender turned down the offer of a reunion ahead of their clash.
"I know him very well from Southampton and we were always together, chatting every day," Mane said.
"We have an excellent relationship but this time I said do you want to meet me and he said no but it's fine, he's a good guy and that's fine.
"I appreciate he's a professional and I know he's going to do everything to defeat me and I'll do the same on my side."