Firmino scored the goal that ultimately proved the winner at Wembley, but had to receive treatment following a collision with Jan Vertonghen .
The Brazil forward was eventually forced off, holding a pad to his eye, and was sent to hospital for further checks which confirmed an abrasion but no threat of lasting damage.
Liverpool were deserving winners but had to endure a nervy finish when Erik Lamela pulled one back for the hosts late on.
Despite seeing his side fail to put the game to bed earlier, manager Jurgen Klopp was delighted the overall display ahead of the huge clash with PSG.
"I'm a very positive person. I see the game and I talk here and analyse it and then I don't think too much about it anymore, to be honest," he said.
"I'm not sure if we can do it on Tuesday and then next Saturday [against Southampton] again. We have to show that.
"It was a very good performance, maybe our best against Tottenham in all the years since I'm here, but I imagine only five per cent less and probably we would have lost.
"Tottenham are not really happy at the moment with the result and not with the performance, but because we were that good it was so difficult for Tottenham. I don't think that Tottenham played badly. That's why we deserved to win.
"But it's over now. Three points. Now we have to go again. We have to play against PSG. They won yesterday without Neymar and [Kylian] Mbappe so they could rest players in the league, but that's Tuesday."