Liverpool had drawn six of their nine Premier League games at Anfield going into this encounter, including four of their last five, and they did not have it all their own way against Newcastle, who took the lead through Daniel Agger's own goal in the 25th minute.
However, Bellamy got Liverpool back on level terms four minutes later before Gerrard's introduction with 31 minutes remaining firmly swung the game in the Reds' favour.
It was Bellamy that put them ahead with a free-kick in the 67th minute, but it was Gerrard that undoubtedly inspired his team-mates and his goal 12 minutes from time was no more than he deserved to cap a terrific cameo. It meant Liverpool had scored three goals in a match since the August 27 win over Bolton.
The night was supposed to be all about Andy Carroll, who was given the role of main striker in the absence of the suspended Luis Suarez, but the centre-forward missed his best chance in the latter stages of the match when he crashed a header against the crossbar from close range.
But, fortunately for Carroll, Bellamy's eye for goal was a lot sharper to ensure Liverpool - for once - were not rueing missed chances.
It was Newcastle, however, that took the lead in the 25th minute in odd circumstances.
Haris Vuckic was walking towards the bench having been hit in the face by Glen Johnson's clearance but Newcastle played on and when Ryan Taylor swung in a cross from the left Yohan Cabaye got a touch before a more crucial one, off the arm of Agger diverted the ball past Jose Reina under pressure from Demba Ba.
However, within four minutes Liverpool were level through Bellamy.
Cheick Tiote made a poor attempt at clearing Charlie Adam's cut-back from the right of the penalty area and Bellamy drive through a crowd of players from 16 yards.
The home side picked up the tempo and Stewart Downing's volley was blocked by Jonas Gutierrez while Martin Skrtel flashed a header just wide of the far post from Bellamy's corner.
Early in the second half Cabaye was lucky to escape punishment after catching Jay Spearing halfway up his shin with a late tackle.
Gerrard replaced Adam just before the hour and the captain's first involvement was to whip in a near-post cross which almost picked out Carroll.
When the England midfielder did find the unmarked striker in five yards of space in the penalty area the £35million signing's first touch let him down badly.
Carroll played a decoy role in Liverpool's second goal but the decisive move came from Danny Simpson.
As Bellamy lined up a 67th-minute free-kick the Newcastle defender decided to back-track to the goalline, allowing Carroll to advance towards Krul. When the set-piece came in Simpson got in the way of his goalkeeper and the ball crept between the two of them.
However, Newcastle would have equalised three minutes later when Ba clipped a narrow-angle shot over Reina - only for Skrtel to clear just inches from the goalline.
Despite Carroll's best efforts he seemed destined not to score when his header rebounded off the crossbar.
Bellamy departed, with blood pouring from a cut above his left eye after a clash with Fabricio Coloccini, to be replaced by Dirk Kuyt for the final 16 minutes.
Not to be outdone Gerrard popped up with a trademark third goal in the 77th minute when he ran from deep to collect Henderson's through-ball and side-foot an angled shot past Krul from the left of the penalty area.
It capped an improved second-half performance and helped ease some of the frustration which had been building up at Anfield.
After their bright start Newcastle have now won one in eight and Alan Pardew needs to arrest the slide.