The Brazilian started on the bench for the midweek Champions League win over Paris Saint-Germain after being caught in the eye by Jan Vertonghen last weekend, with Daniel Sturridge starring in his place.
The 2017 Champions League Runners-up took the lead when Daniel Sturridge scored with a thumping header in the 30th minute.
Then Mbappe stunned the raucous Anfield crowd with a clinical finish only to see Firmino grab the glory.
After the Liverpool game, Warnock said: "When you get Daniel fit and firing, you can not ignore him".
But Liverpool could have been much further ahead had Salah and Mane combined better in attack. Let us know what you think by leaving a comment below.
Yes, he has had his injury problems and his Liverpool career looked to be over in January when he went to West Brom on loan.
The stats surrounding his display against PSG are as bad as you might think with very little positive coming from the feet of Salah as the Champions League got underway. "I thought he was different class for 70 minutes, he was brilliant", added Robertson. Sturridge didn't get there in time, and it was Areola who paid the price.
For anyone who saw them play in the 1970s and 1980s, the name Liverpool is synonymous with complete domination, silverware, and thrilling football.
UEFA have introduced a handful of earlier kick-offs in every Champions League midweek this season, and it was still light at the Camp Nou as Barcelona kicked off against PSV Eindhoven in Group B.
Those two had not played well though, and Mbappe was caught in possession just before Firmino, on as a substitute, struck the victor in the second minute of stoppage time.
After going so close to winning it a few months ago, Liverpool might have needed something to give them the belief that their run to the final can happen again. "We played a midfield who played a lot of times last season together, that was the reason for that performance".