Lampard has taken so much stick this season and even lost his job as penalty taker to Michael Ballack after missing one against Charlton.
But with Ballack suspended at Craven Cottage he thumped home a spot-kick after 72 minutes to break Fulham's hearts in a match in which the home side had battled superbly to that point.
As is the way of these things, the England midfielder then scored a superb second, firing home a trademark effort from the edge of the area following a Didier Drogba lay-off. It clinched a fantastic result for the champions who had to play the match without captain John Terry because of a back injury.
But it was terribly harsh on Fulham who had put absolutely everything into the opening 70 minutes without reward.
They did superbly in the first half to both keep Chelsea at bay and to pose problems of their own.
With Michael Brown buzzing around midfield like a man possessed and Liam Rosenior getting forward at every opportunity down the right flank, the visitors looked in trouble.
The Blues began the match without Terry, who injured his back before the game and was unable to play. That meant Paulo Ferreira stepping in at centre-back because first choice replacement Khalid Boulahrouz was ill with Geremi coming into the side at right-back.
It looked like a real chance for Fulham to repeat their heroics of last season when they beat the champions 1-0 here at Craven Cottage.
So the only disappointment was that manager Chris Coleman chose to play only one man up front, in the shape of Collins John, and fill his midfield instead.
It worked to an extent because Chelsea were rattled by Fulham's high-energy performance, but the problem for Fulham was that they never looked like creating chances. The only real one of the first half saw Wayne Routledge send in a curling shot from inside the area, which Petr Cech palmed away with both hands.
In contrast, Chelsea had Arjen Robben back from injury and firing on all cylinders. He came close to opening the scoring with a stunning left-foot shot that curled and swerved in the air from 25 yards before smashing against the crossbar after 24 minutes.
After the break Fulham continued their high-energy approach and if anything upped the tempo as the home crowd roared them on.
They almost grabbed a lead when Lampard's mistake allowed in Brown, but as he strode into the area Cech flung himself bravely and forcefully at his feet to deny him a goal. Papa Bouba Diop then missed a glorious chance for the home side, heading tamely wide at the far post from a Franck Queuedrue free-kick when it seemed easier to score. And that really was the turning point.
Chelsea brought on Salomon Kalou to liven things up and Chelsea suddenly moved up gear. But it took a terrible mistake from Liam Rosenior to gift them a lead when he fell to the floor as he tried to challenge Kalou in the box and clearly handled the ball.
Lampard smashed the penalty straight down the middle and minutes later he strode onto Drogba's flick to drive home Chelsea's second and decisive goal.