The Reds were deservedly behind to Ezequiel Lavezzi's goal after
a dire first-half performance but the England midfielder's
introduction at the interval changed the dynamic.
Gerrard, as he always has, led from the front and scored three
goals in the final 15 minutes to extend Liverpool's lead at the top
of Group K.
It also made it two wins and two draws in the last four matches
and ensured the side's mini-revival did not come crashing to an end
before it had chance to gather momentum.
That Gerrard made such a difference highlighted the deficiencies
on the playing staff at Anfield, with the side operating the vast
majority of the second half with five central midfielders in a
variety of other positions.
The captain put the rest of his team-mates to shame.
Newly-appointed director of football strategy Damien Comolli,
watching alongside owner John Henry, must be wondering how he is
expected to bring in talent to match that of Gerrard's, such was
the midfielder's influence on the game.
But both Henry and Comolli would have been disappointed with how
quickly Liverpool were put on the back foot by the lively visitors
in the first half.
Equally worrying was the number of times they gave the ball
away, a failing which ultimately cost them as one such occasion led
to Napoli's goal.
Lavezzi looked dangerous from the start and his shot forced a
corner off Paul Konchesky, with his next intervention releasing
Edinson Cavani through the inside-left channel only for the
Uruguayan to blaze over.
The provider was slightly closer himself when he seized on a
misplaced pass by Jonjo Shelvey to run at the Liverpool defence and
fire a shot just wide of Jose Reina's left-hand post.
Pressure was starting to build and Glen Johnson, returning from
a thigh injury after a four-match absence, was the first player to
be booked for hacking at the back of Cavani's legs before the Reds
cracked in the 28th minute.
Christian Poulsen's aimless back-header in the centre circle was
picked up by Cavani on the left and he slipped a pass through to
Lavezzi who calmly steered the ball under Reina, sparking wild
celebrations for the visiting fans - many of whom had managed to
acquire tickets in a corner of the main stand.
The response was for David Ngog to stab wide from Poulsen's pass
and Johnson to force a regulation save out of Morgan de
Sanctis.
But manager Roy Hodgson had already seen enough and sent Gerrard
out to warm-up 10 minutes before the interval, with the captain
reappearing for the second half at the expense of Milan
Jovanovic.
It took just 11 seconds for Gerrard to get into the game,
winning a tackle with typical aggression before moments later
inducing a foul from Andrea Dossena which earned the former
Liverpool defender a booking.
The England midfielder's presence had certainly had the desired
effect, even if it did mean the side now had even less width with
five central midfielders on the field.
Ngog and Shelvey wasted chances before Meireles missed the
target from eight yards after latching on to Ngog's loose pass.
Gerrard curled a free-kick just wide from the edge of the
penalty area but it was his sheer determination which brought the
equaliser in the 75th minute.
Shelvey's run appeared to be petering out when Dossena did his
former club - where he endured a miserable time - a huge favour by
diverting the ball towards De Sanctis.
Gerrard sensed an opportunity and charged in with his lunge
enough to divert the ball past the goalkeeper.
Salvatore Aronica's 88th-minute trip on Johnson presented the
captain with a penalty to double his tally and he duly obliged.
In the directors' box Henry punched the air but he had barely
sat down before Gerrard completed his hat-trick and sealed the
victory, cleverly dinking the ball over De Sanctis from substitute
Lucas Leiva's through-ball.