Jürgen Klopp thinks that Liverpool stepped up to the next level, by proving there is "no mountain they can not climb", after a breathless return to the Champions League brought a dramatic stoppage-time victory over Paris Saint-Germain.
Thomas Meunier replied before half-time and Kylian Mbappe levelled in the 83rd minute before Firmino sent the home fans wild.
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.
It was the 29-year-old's first start in the competition for Liverpool and his first start in the Champions League since he was part of Chelsea's title-winning team in 2012.More news: Woods, Fowler tied for East Lake lead
"Then you can bring Bobby Firmino on and that helps a lot".
He proved himself to still be the club's best finisher when he pounced on his first chance to power a close-range header past Alphonse Areola from Robertson's cross.
"PSG aren't going to pay for it in the French league, where Neymar and Mbappe don't track back and don't run around too much and still win comfortably, but that will probably work against PSG in the latter stages of the Champions League".
Six minutes later the Reds doubled their lead when PSG defender Juan Bernat tripped Georginio Wijnaldum in the area and Milner slotted home the penalty.More news: Researchers may have found Captain Cook's ship Endeavour
At this point the primary danger appeared to be Liverpool getting swept away by the euphoria and not managing the game properly.
But it was two strokes of luck which allowed PSG to pull one back just before half-time.
There could now be doubt about Salah's starting place in the team with Daniel Sturridge impressing up front and Xherdan Shaqiri, who replaced him against Paris, chomping at the bit to get his first Premier League start in a Liverpool shirt.
"To make those changes and still come out on top against PSG, who are flying, that will set them in good stead". And Liverpool are doing all the right shaping at all the right times.More news: This app by Google will turn off your child's phone during dinner