Roy Hodgson’s team had found themselves behind at the break thanks to Shkodran Mustafi’s opener, but four minutes into the second half they drew level when Andros Townsend scored against the Gunners in SE25 for the second successive season and give Palace hope of continuing their best run of top-flight form in 27 years.
But Sanchez’s quick-fire brace just after the hour mark put the Gunners in control until James Tomkins headed in a late corner to set up a grandstand finish, but the north Londoners earned the derby day bragging rights and ensured that Arsene Wenger tasted victory in what was his record-equalling 810th Premier League appearance as a manager.
The home side began like a team who hadn’t tasted defeat in their previous eight games and enjoyed lengthy spells of possession in the Gunners’ half, and on 15 minutes they came a whisker away from taking the lead but unlike the corresponding fixture last season, Yohan Cabaye couldn’t quite find the net from long range as his low blast skidded wide.
That warning saw Arsenal crank up the pressure and they became the dominant side for the rest of the half. As they worked through their gears they created a few threatening moments in the final third including a Jack Wilshere blast from 25 yards that fell straight to Julian Speroni, but on 25 minutes they found a way through the Eagles defence.
A free-kick into the box was cleared out as far as Mesut Ozil who found Alexandre Lacazette inside the box. After seeing a cross blocked, the club record signing got the ball onto his left foot before firing goalwards from a tight angle, and after Speroni parried it away, it fell invitingly for Mustafi who produced a composed first-time finish to hand the lead to Wenger’s team.
It was very nearly 2-0 four minutes later when an excellent incisive pass by Sanchez allowed Ozil to prod goalwards but Speroni showed fine reactions to stick out a hand and deflect it away, and the chances continued to rack up as Lacazette rippled the side-netting after creating a shooting chance after many twists and turns, and then somehow the visitors squandered a three-on-two opportunity after Ozil broke through and rounded Speroni.
There was a brief glimmer for Palace amongst those opportunities when Wilfried Zaha flashed an effort wide of the mark after cutting inside off the left flank, but their fortunes were to change just four minutes after the restart.
Playing with some fire in his belly, Zaha burst into life on the left and after some textbook trickery saw him escape from Callum Chambers, he cut the ball back to the penalty spot where Townsend was waiting to lash the ball first-time past Petr Cech and score for the first time since registering in the 3-0 win against the Gunners last April.
That saw Hodgson’s team grow in confidence and not long after pulling level Jeffrey Schlupp blasted into the side-netting after latching onto a Zaha through-ball, but the good mood around Selhurst was punctured 12 minutes later as Arsenal netted twice in quick succession to put clear daylight between the sides.
Firstly, Chambers lofted a high ball into the box which once again dropped to Lacazette, and after he got it under control he received a shout from Sanchez to lay it off, and the Chilean rifled a powerful blast towards the near post which zipped through James Tomkins’ legs and despite Speroni getting a glove to it, it proved too venomous.
And four minutes later, the Palace keeper was beaten again by his fellow South American when Jack Wilshere received time and possession inside the centre circle and played a fine pass into the onrushing Sanchez’s feet, and a delicious first touch set him up perfectly to slide into the corner and virtually put the game to bed with 24 minutes to play.
Only another good stop by Speroni prevented Hector Bellerin from adding a fourth when once again another long ball over the top caused the home defence issues, but with 10 minutes Palace threw everything at their opponents.
The onslaught began when Zaha screwed a header wide when well-placed, and soon after Bakary Sako blazed horribly over before seeing another attempt deflect inches wide, but from the resulting corner, Tomkins headed in Townsend’s delivery to net his first goal for over a year with just over a minute of normal time remaining.
Despite the Eagles’ best efforts though, they couldn’t find another equaliser and the impressive lengthy unbeaten run finally came to an end.
Palace: Speroni, Kelly (Fosu-Mensah 80), Tomkins, Dann, Schlupp, Townsend, Milivojevic, Cabaye (McArthur 53), Loftus-Cheek (Sako 70), Zaha, Benteke. Subs not used: Hennessey, Van Aanholt, Riedewald, Puncheon.
Arsenal: Cech, Chambers, Mustafi, Koscielny, Bellerin, Wilshere, Xhaka (Maitland-Niles 86), Kolasinac, Ozil, Sanchez, Lacazette (Coquelin 75). Subs not used: Ospina, Holding, Iwobi, Walcott, Welbeck.