Reds midfielder Georginio Wijnaldum admitted the injury to Salah so early in the contest affected their performance.
"I think it was a big blow for us, it seemed like a big blow for us the way the way we reacted after his injury," said Wijnaldum.
"I think when he was on the pitch we did it well for 25 minutes but (after the injury) there was less than before.
"Those things happen and we had to deal with it but it was difficult."
Asked what Klopp said at half-time, the Holland international added: "He said that it looked like we were devastated about Mo but we had to let it go and change because it could not change.
"Sometimes those things happen in football. It is hugely frustrating but we can't change it."
Egypt's team doctor Mohamed Abou El-Ela said in a statement that, according to information from Liverpool's medical staff, Salah has sustained only ligament damage and he remained optimistic he would still feature in the World Cup.
