The former West Ham United star has endured an injury-ravaged campaign but was in the right place at the right time as he steered Didier Drogba's 29th-minute cross past Jose Reina.
Jose Mourinho's side dominated the first half and should have been more than one goal ahead at the break, but Liverpool improved in the second period, particularly after Peter Crouch had come on for the ineffective Craig Bellamy.
Chelsea started brightly and they almost took a seventh-minute lead when a great header by Drogba set up Frank Lampard who smashed a shot goalwards, only for Reina to make a smart stop.
As the hosts continued to press, Andriy Shevchenko saw Reina off his line but his shot was too high and drifted over the bar
In the 17th minute the unmarked Joe Cole raced towards goal, but Drogba's attempted pass to him was poor and Reina was able to race off his line to avert any danger.
Shevchenko then lashed a cross-cum-shot across goal after being set up by Drogba, but there was too much pace on the ball for the onrushing Joe Cole as the one-way traffic continued.
Joe Cole then found Drogba, but the Ivory Coast international tried to glance a header home, only to miss the ball as Reina charged off his line.
Lampard drilled a free-kick narrowly wide with Reina beaten before Chelsea took a deserved lead.
After good play by Ricardo Carvalho, Drogba beat Daniel Agger and crossed for Joe Cole to stab the ball home.
Eight minutes before the interval, in a rare first-half attack by Liverpool, Gerrard looped a header over the bar.
After such a humdrum opening 45 minutes by the visitors, Liverpool started the second half brightly with substitute Crouch causing problems in the Blues defence which allowed Gerrard to drill a shot towards goal. However, Petr Cech made an outstanding low save to deny the midfielder.
The Reds continued to probe but, although they had much more possession than in the first half, they were unable to carve open the well-drilled Chelsea defence.
Indeed the Blues finished the game strongly, and Drogba headed narrowly wide before Reina made another stunning save to deny Lampard.
But there were no more goals to leave both sides still believing they can reach next month's Champions League Final in Athens.