Rafael Benitez's side are now a point above the Gunners with a game in hand as their Spanish interim manager prepares to take the Blues to his former club Liverpool on Sunday.
The victory, which ended a run of three Premier League defeats away from home, came thanks to a clinical finishing display that put the game out of Fulham's reach before the interval.
In keeping with a run of one defeat in their last seven Premier League games, Martin Jol's side were in the ascendancy early on but they once again fell to defeat by their west London neighbours, extending a remarkable run of just one win in 33 years.
Luiz finds joy away from home
David Luiz's strike was his first Premier League goal away from Stamford Bridge. His first five in the English league had all come on home soil.
Had Ruiz scored from Sascha Riether's right-wing cross or John Arne Riise injected more power into his shot halfway through the first half, the picture might have more closely reflected the game's flow.
However, it was Chelsea who took the lead, and in spectacular style as Luiz collected Eden Hazard's square ball and fired a stunning drive into the top corner.
Fulham almost replied instantly when Emanuelson cut in from the left and his effort was superbly tipped around the post by Cech. Dimitar Berbatov was then narrowly off target with another strike.
The hosts soon paid the price as Chelsea went further ahead two minutes before the break.
Jol frustrated after 'harsh' defeat
Frank Lampard, aiming to take a step closer to Bobby Tambling's record of 202 goals for Chelsea on his 600th appearance, fired in a swerving free-kick that Schwarzer chose to save with his chest.
The resulting corner was initially cleared, but Juan Mata crossed to the back post where Terry thumped his header in.
Fulham's first-half woe was summed up by a booking for Ruiz, who stumbled under close attention from Terry and was booked for diving by referee Mike Dean.
Chelsea began the second half knocking the ball about with the confidence of a side with a two-goal cushion and Mata was inches away from making it three when he failed to reach Torres' cross.
At the other end, in a sign that it was not to be Fulham's night, Mladen Petric managed to divert team-mate Philippe Senderos's goalbound header over the bar while standing on the line.
Minutes later, Terry grabbed his second from another corner to put the game out of sight, nodding in at the back post after he was found by Torres' near-post header.
Fulham boss Martin Jol on Bryan Ruiz's booking for diving:
"If that is a dive, it's ridiculous, he lost his balance. Of course a player can lose his balance and fall down but it's never a booking. The only thing I said [to the referee] was that is why I can see you never played and I think he agreed.
"We couldn't get the goal we should have had in the first few minutes; Dimitar Berbatov had a few shots, Urby Emanuelson, Giorgos Karagounis and Mladen Petric had chances, but we didn't get the break and then it's always difficult. And then 3-0 if you didn't see the game, it was a bit harsh."
Chelsea boss Rafael Benitez on David Luiz's goal:
"I have seen him in training sessions scoring lots of goals and free kicks so he has the ability and the quality, he's very good player.
"Obviously to win is very important, to win with a clean sheet and scoring three goals is more important and to win a derby is even more important, so there are lots of positives.
"You talk about other teams [challenging for the Champions League], they have also players with experience. The main thing is to concentrate and use the quality that we have and stick together as a team. Everybody knows we have to be ready for every game, change players - they have to be ready because we still have two games a week."
Full Time The final whistle goes and the game is over.
Free kick awarded for an unfair challenge on Kerim Frei by Mikel. Strike comes in from Hugo Rodallega from the free kick, blocked by John Terry.
Emmanuel Frimpong challenges Branislav Ivanovic unfairly and gives away a free kick. Free kick taken by David Luiz.
The ball is crossed by Sascha Riether, John Terry makes a clearance.
Handball decision goes against Hugo Rodallega. David Luiz restarts play with the free kick.
Effort from just outside the area by Demba Ba goes over the bar.
Victor Moses delivers the ball.
Sascha Riether produces a cross, comfortable save by Petr Cech.
Short corner taken by Emboaba Oscar.
Free kick awarded for an unfair challenge on Emboaba Oscar by Urby Emanuelson. Mikel takes the direct free kick.
Substitution Kerim Frei on for Mladen Petric.
Corner taken left-footed by Bryan Ruiz from the left by-line to the near post, clearance made by Branislav Ivanovic.
Substitution Demba Ba on for Juan Mata.
Free kick awarded for an unfair challenge on Eyong Enoh by Juan Mata. Eyong Enoh restarts play with the free kick.
The ball is sent over by Victor Moses.
Foul by Hugo Rodallega on Branislav Ivanovic, free kick awarded. David Luiz takes the free kick.
Substitution Emmanuel Frimpong is brought on as a substitute for Giorgos Karagounis.
Emboaba Oscar takes a corner.
Substitution Mikel joins the action as a substitute, replacing Nascimento Ramires.
Fernando Torres provided the assist for the goal.
70:50 Goal scored
Goal! - John Terry - Fulham 0 - 3 Chelsea John Terry scores a headed goal from inside the six-yard box. Fulham 0-3 Chelsea.
Giorgos Karagounis takes a shot.
Foul by Juan Mata on Eyong Enoh, free kick awarded. Direct free kick taken by Giorgos Karagounis. Corner taken right-footed by Giorgos Karagounis from the left by-line to the near post, Philippe Senderos takes a shot. Victor Moses takes a shot. Inswinging corner taken from the left by-line by Juan Mata.
Substitution Emboaba Oscar comes on in place of Eden Hazard.
Inswinging corner taken by Urby Emanuelson from the left by-line played to the near post, clearance made by Nascimento Ramires.
Substitution John Arne Riise goes off and Hugo Rodallega comes on.
Frank Lampard takes a shot. Save by Mark Schwarzer.
Fernando Torres takes a shot. Blocked by Philippe Senderos.
Frank Lampard takes a shot. Blocked by Eyong Enoh.
Mladen Petric concedes a free kick for a foul on David Luiz. Free kick taken by Juan Mata.
Mladen Petric has an effort at goal from outside the box which goes wide right of the goal.
Victor Moses gives away a free kick for an unfair challenge on Eyong Enoh. Philippe Senderos takes the direct free kick.
Sascha Riether delivers the ball, clearance by John Terry.
Frank Lampard concedes a free kick for a foul on Giorgos Karagounis. Giorgos Karagounis takes the free kick.
Centre by Fernando Torres.
The assistant referee flags for offside against Dimitar Berbatov. Free kick taken by David Luiz.
Brede Hangeland challenges Fernando Torres unfairly and gives away a free kick. David Luiz restarts play with the free kick.
Inswinging corner taken right-footed by Giorgos Karagounis from the left by-line to the near post, Branislav Ivanovic manages to make a clearance.
The ball is crossed by Sascha Riether, clearance made by Branislav Ivanovic.
The ball is delivered by Mladen Petric.
Juan Mata fouled by Giorgos Karagounis, the ref awards a free kick. Free kick taken by Frank Lampard.
Free kick taken by Ryan Bertrand.
Booking Philippe Senderos goes into the book for unsporting behaviour.
Victor Moses fouled by Philippe Senderos, the ref awards a free kick.
The second half has started.
45:00 +1:16 Half time
Half Time The first half comes to an end.
Ryan Bertrand concedes a free kick for a foul on Giorgos Karagounis. Free kick taken by Giorgos Karagounis.
Direct free kick taken by Petr Cech.
Booking Booking for Bryan Ruiz for unsporting behaviour.
Juan Mata provided the assist for the goal.
42:06 Goal scored
Goal! - John Terry - Fulham 0 - 2 Chelsea John Terry finds the net with a headed goal from close in. Fulham 0-2 Chelsea.
Giorgos Karagounis gives away a free kick for an unfair challenge on Victor Moses. Direct strike on goal from the free kick comes in from Frank Lampard, save by Mark Schwarzer. Eden Hazard takes the inswinging corner, clearance by Bryan Ruiz.
Dimitar Berbatov has a shot on goal from outside the box which misses left.
The ball is swung over by Ryan Bertrand, save by Mark Schwarzer.
Foul by Eyong Enoh on Juan Mata, free kick awarded. David Luiz takes the direct free kick.
A cross is delivered by Juan Mata, Brede Hangeland makes a clearance.
Fernando Torres produces a right-footed shot from inside the area that clears the bar.
Urby Emanuelson takes a shot. Save made by Petr Cech. Inswinging corner taken right-footed by Giorgos Karagounis played to the near post, clearance made by Fernando Torres.
Nascimento Ramires produces a drilled right-footed shot from 25 yards. Philippe Senderos gets a block in.
The ball is sent over by Branislav Ivanovic.
The assist for the goal came from Eden Hazard.
29:36 Goal scored
Goal! - David Luiz - Fulham 0 - 1 Chelsea David Luiz finds the net with a goal from 35 yards to to the top right corner of the goal. Fulham 0-1 Chelsea.
The ball is crossed by Victor Moses.
John Arne Riise takes a shot. Save by Petr Cech.
Centre by Victor Moses.
Free kick awarded for a foul by Nascimento Ramires on Eyong Enoh. Free kick taken by John Arne Riise.
Frank Lampard takes a shot. Eyong Enoh gets a block in.
Giorgos Karagounis takes a shot from just outside the penalty area clears the crossbar.
Dimitar Berbatov takes a shot. Blocked by John Terry. Corner from the left by-line taken by Giorgos Karagounis, save by Petr Cech.
The ball is crossed by Branislav Ivanovic, save by Mark Schwarzer.
Unfair challenge on Eden Hazard by John Arne Riise results in a free kick. Direct free kick taken by Eden Hazard.
Unfair challenge on Giorgos Karagounis by Fernando Torres results in a free kick. Free kick taken by Giorgos Karagounis.
Mladen Petric crosses the ball in from the free kick, comfortable save by Petr Cech.
Booking Booking for Branislav Ivanovic for unsporting behaviour.
Free kick awarded for a foul by Branislav Ivanovic on Mladen Petric.
Inswinging corner taken from the right by-line by Juan Mata.
Branislav Ivanovic crosses the ball, clearance made by Brede Hangeland.
Free kick awarded for an unfair challenge on Eyong Enoh by Nascimento Ramires. Giorgos Karagounis restarts play with the free kick.
Foul by Ryan Bertrand on Bryan Ruiz, free kick awarded. Direct free kick taken by Giorgos Karagounis.
Branislav Ivanovic delivers the ball, Giorgos Karagounis manages to make a clearance.
The ball is delivered by Branislav Ivanovic, Frank Lampard takes a shot. Save by Mark Schwarzer.
Dimitar Berbatov takes a shot. Blocked by Nascimento Ramires.
Unfair challenge on Fernando Torres by Eyong Enoh results in a free kick. Free kick taken by Nascimento Ramires.
The ball is sent over by John Arne Riise, John Terry manages to make a clearance.
The ball is sent over by Sascha Riether, Strike from close range by Bryan Ruiz clears the bar.
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