The 32-year-old crashed home a second-half spot kick to propel Arne Slot's side to their sixth win from six in the league phase, although they had to rely on returning number one Alisson Becker to keep their plucky hosts at bay several times.
In a frenetic and end-to-end first 45 minutes of action at Estadi Montilivi, both sides showed plenty of attacking endeavour without any defensive ruggedness to go with it, as both goalkeepers had plenty to do early doors.
Slot placed his faith in Alisson, who made an immediate return to the first XI two months after suffering a hamstring injury, and the Brazilian saved the visitors' bacon on more than one occasion in the opening period.
As well as making some crucial one-on-one interventions, Alisson made a terrific full-length save to thwart Yaser Asprilla, while at the other end, Joe Gomez was denied a long-awaited first Liverpool goal by a reaction stop from Paulo Gazzaniga.
The chaos continued to ensue at the start of the second period, but it took a spot kick from the scintillating Salah to separate the two outfits, as the Egyptian dispatched his 50th European goal for the Reds and 50th overall in the Champions League - including qualifying - after Donny van de Beek's foul on Luis Diaz.
Michel responded to Liverpool's opener by strangely taking off the industrious Arnaut Danjuma and Bryan Gil, and while the hosts kept believing right to the death, an Alisson and Salah-inspired Reds side stood firm.
On the cusp of confirming a top-eight finish and automatic qualification for the last 16, Liverpool are still looking down on the other 35 teams in the Champions League table, while Girona sit in a lowly 30th, three points below the playoff places after their fifth loss from six UCL matches.
GIRONA VS. LIVERPOOL HIGHLIGHTS
Mohamed Salah goal vs. Girona (63rd min, Girona 0-1 Liverpool)
How this game got to the hour mark without a goal is anybody's guess, but Liverpool finally have the deadlock breaker, as Salah nets goal number 16 for the season.
The Reds are belatedly awarded a spot kick after Donny van de Beek takes Luis Diaz's shoe off while the Colombian was lining up a volley, and Salah clinically sends Gazzaniga the wrong way for his 50th European goal in Liverpool colours.
MAN OF THE MATCH - ALISSON BECKER
In spite of Caoimhin Kelleher's exceptional work in between the posts during Alisson's absence, Slot has made it clear that the latter is still his undisputed number one, and the South American proved exactly why with a magnificent welcome-back display.
Flaunting his acrobatic excellence, top reactions and unrivalled one-on-one ability in equal measure, Alisson made five saves in total - four of which came from inside the box - and he was quick off his line to make a couple of clearances when the situation demanded it.
GIRONA VS. LIVERPOOL MATCH STATS
Possession: Girona 38%-62% Liverpool
Shots: Girona 13-14 Liverpool
Shots on target: Girona 5-7 Liverpool
Corners: Girona 5-8 Liverpool
Fouls: Girona 11-8 Liverpool
BEST STATS
WHAT NEXT?
On matchday six of the Champions League, Liverpool play host to 2020-21 Ligue 1 champions Lille on January 21, one day before Girona face another difficult assignment away to AC Milan.
In terms of more pressing matters, the Reds welcome Fulham to Anfield in Saturday's Premier League showdown, while Michel's side travel to Mallorca in La Liga on the same afternoon.
Written by
Ben Knapton