Gabriel opened the scoring from a corner early on and the centre-back thought he had a second, but it went down as own-goal by Eagles goalkeeper Dean Henderson.
Arsenal were worthy winners and they dominated much of the game, with Leandro Trossard making it 3-0 after half-time.
Substitute Gabriel Martinelli added two late on - and the win moves Arsenal up to third in the Premier League and two points off leaders Liverpool.
Simon Collings was at Emirates Stadium to see Arsenal in action...
David Raya 8
One of his best performances in an Arsenal shirt. Distribution was excellent and he played a big hand in the third goal.
Ben White 6
A steady performance. Did not get forward on the overlap that much, but kept Eberechi Eze fairly quiet.
William Saliba 7
Oozed class with his performance, which included one audacious turn inside his box to lose an attacker. Barely put a foot wrong all game.
Gabriel 8 | Star player
Opened the scoring with a header from a corner and thought he had another, but it was given as an own-goal. Dominant defensively.
Oleksandr Zinchenko 7
Back in the squad after returning from injury. Calm in possession, but did well defensively too as Palace tried to target his side aerially.
Martin Odegaard 6
Set up a few chances with some cute touches in the box. Found it difficult to break Palace down.
Declan Rice 7
A surprise assister for Arsenal's opener as he swung in a corner for Gabriel to head home. Came off early amid concerns he could be injured.
Kai Havertz 6
A quiet performance from the German. Some nice touches here and there, but struggled to find space.
Bukayo Saka 6
Unlucky not to have an assist after Gabriel's second header went down was an own-goal. Didn't have many chances and Palace dealt well with him.
No goal but his link-play was, once again, good. Setup Arsenal's third goal by countering well with Trossard.
Leandro Trossard 7
Struggled in the early stages but got better as the match went on. Took his goal well after missing a good chance just before it.
Gabriel Martinelli (Trossard 69') 8
Dropped for Trossard and made a point with two goals off the bench.
Emile Smith Rowe (Havertz 69') 7
Got a great reception from the fans when coming on. A really bright cameo.
Jorginho (Rice 73') 7
Came on for Rice, who looked injured, and setup Arsenal's fifth.
Eddie Nketiah (Jesus 81') N/A
Jakub Kiwior (Gabriel 81') N/A
Subs not used: Ramsdale, Kiwior, Cedric, Walters, Nelson, Nketiah