A dreadful first-half display from the visitors enabled the Gunners to race into a three-goal lead at the break as Martin Odegaard struck twice inside the first 31 minutes before Gabriel Jesus added a third from close range.
Pierre-Emerick Aubameyang made a surprise start against his former club but was replaced at half-time after touching the ball just nine times and with Kai Havertz leading the line instead, Chelsea improved somewhat after the break. Noni Madueke scored his first Chelsea goal on 65 minutes with a scruffy finish from Mateo Kovacic's through-ball but the damage had already been done as Arsenal secured their first win in five matches.
Arsenal suffered an injury scare at the end when defender Gabriel Magalhaes limped off with what appeared to be a muscular problem.
Caretaker boss Frank Lampard has now lost all six of his matches in charge of Chelsea while Arsenal return to the Premier League summit by two points having played two matches more than Manchester City, who face West Ham at Etihad Stadium on Wednesday evening.
1. Shambolic Chelsea gift Arsenal chance to stay in title fight
After four games without a win and Manchester City moving into the top spot of the Premier League table, Arsenal's confidence was shaken, leaving them a fragile entity at kickoff here. In those four losses, Liverpool, West Ham, Southampton and Man City had causes to rally around, whether that was chasing Champions League qualification, avoiding relegation or trying to win the league.
But Chelsea, manager-less and detached in mid-table, had nothing to bring them together beyond caretaker boss Frank Lampard demanding a show of pride in a London derby. That rallying cry fell on deaf ears.
Even in a season of struggles, Chelsea were almost incomprehensibly bad here at the Emirates, allowing the Gunners to find their stride from a slow start. While Martin Odegaard's 18th-minute opener was well-taken, the space he had in which to take aim was laughable.
In truth, Chelsea's defending for all three first-half goals was shambolic, leading to the gleeful home fans to chant: "Are you Tottenham in disguise?" To be fair, Chelsea weren't far away from having to consider issuing a refund to travelling supporters just as Spurs did after last month's 6-1 defeat at Newcastle.
Chelsea's camp is not a happy one these days. Thiago Silva could be seen arguing with Ben Chilwell after Arsenal's second goal and although there was a modicum of improvement in the second half -- epitomised by Noni Madueke's 65th-minute consolation -- the end of the season cannot come soon enough.
By contrast, the Gunners got a vital morale-boost at a pivotal time and let City know they are still in the hunt ahead of Sunday's vital trip to Newcastle.
2. Lampard's Aubameyang gamble backfires, epitomises terrible Chelsea
Chelsea have indeed been badly struggling for goals of late, scoring just once in five games under Lampard before this. But the rationale in suddenly starting Aubameyang is surely based on how he was abruptly transferred to Barcelona by Arsenal in January 2022 -- a ploy for revenge from the striker -- rather than any signs of encouragement from his performance against Brentford last weekend.
It was a gamble that completely backfired.
On Aubameyang's last start -- the reverse fixture -- he had eight touches and lasted 64 minutes. Here, he had nine in 45 minutes and four of those were kickoffs.
It was the nadir of a truly shambolic display from Chelsea, who have now lost all six games under Lampard, the club's worst run since November 1993.
Facing Arsenal is a reminder of Aubameyang's awkward past. His present is no better these days, and so it is inevitable his future now lies elsewhere.
3. Arteta and his players get a breather with squad rotation
There have been signs of physical and mental fatigue as Arsenal have surrendered the title advantage to Man City in recent weeks.
As such, Arsenal manager Mikel Arteta made three changes on Tuesday to freshen things up: Jakub Kiwior, Jorginho and Leandro Trossard replaced Rob Holding, Thomas Partey and Gabriel Martinelli. That latter trio were arguably Arsenal's three worst performers in last week's defeat at City, and so whether these specific alterations were also designed as a warning against dropping standards, the desired outcome was a much-improved display.
The game was over as a contest by the break, enabling Arteta to continue the theme of getting a breather into his certain players, bringing off Bukayo Saka and Oleksandr Zinchenko for the final 16 minutes here.
The Gunners' reliance on a creative core over the entire season is clear: with his brace against Chelsea, Odegaard became the third Arsenal player to reach 20+ goals and assists combined in the Premier League this season, after Saka (24) and Martinelli (20). Arsenal are the only side with three or more players to have reached this milestone.
Best and worst performers
Best: Martin Odegaard, Arsenal
Took advantage of the freedom of north London to finish well twice with his left foot.
Best: Jorginho, Arsenal
Helped Arsenal control the game in midfield with a 90 per cent pass competition rate from 70 attempted passes.
Best: Gabriel Jesus, Arsenal
Gave Arsenal impetus at the top of the pitch and his perseverance was rewarded with his 10th goal of the season.
Worst: Pierre-Emerick Aubameyang, Chelsea
Hauled off at half-time after an anonymous showing -- a miserable return to his former club.
Worst: Raheem Sterling, Chelsea
Non-existent as an attacking threat. Completed just 14 of 24 passes in 71 minutes and only 28.6 per cent in the final third.
Worst: Wesley Fofana, Chelsea
Looked particularly shaky as Arsenal swarmed all over Chelsea in the first 45 minutes.
Highlights and notable moments
Martin Ødegaard started off the festivities for Arsenal within the first 18 minutes. Granit Xhaka crossed the ball into the middle and Ødegaard, standing at the top of the box, smashed it in with perfect placement, knocking it off the inside of the crossbar and in.
From there, Arsenal were in cruise control and Ødegaard scored again in the 31st minute.
Gabriel Jesus joined in on the fun in the 34th minute, finishing off a scramble in the box to make the score 3-0.
After the match: What the managers and players said
Arsenal manager Mikel Arteta on his team's performance: "The first 60 minutes, I thought the team played really well. We need to be us, and that was everything I want to see from our team. Speed, quality, movement, two beautiful goals, we connected with our crowd and created an incredible atmosphere. They have been incredibly supportive of what we have done and we wanted to earn the right to be top of the league. We are, and happy to be there."
Arteta on the apparent injury to Gabriel Magalhaes: "He could not carry on. We have to assess him -- he was not comfortable."
Chelsea manager Frank Lampard on his team's performance: "We were too nice to play against in all aspects in the first half. In the second half we played much more like a team that has a threat up top. In the first half we were too easy to play against."
Key stats (provided by ESPN Stats & Information research)
Chelsea have lost all six of their games (all competitions) since Frank Lampard took over as caretaker manager. The last time they lost six straight was October-November 1993.
Chelsea have lost their last 10 league matches when conceding first, and their last league win when conceding first was Oct. 1, 2022 against Crystal Palace.
Martin Ødegaard scored his 13th and 14th league goals of the season for Arsenal. He is now one behind Gabriel Martinelli for most Premier League goals on the team. This is Ødegaard's third Premier League brace on the season, which is the most on the team. Ødegaard has never scored a hat trick in his professional career.
Arsenal now have four players with 10+ league goals on the season (Martinelli, Ødegaard, Saka, Jesus). This is the first time they have had four players with 10+ goals each since the 2012 Arsenal team (Walcott, Cazorla, Giroud, Podolski).
Arsenal: The first-place Gunners visit third-place Newcastle United on Sunday, May 7 for a match that could have major implications in both the Premier League title race and the top-four Champions League race.
Chelsea: The mid-table Blues visit fellow mid-tier AFC Bournemouth for a Premier League fixture on Saturday, May 6.