Perez made a perfectly-timed run to meet Yedlin’s cross with a fine finish that flashed by Petr Cech at his near post.
The Spanish forward’s third goal in his last three appearances was a clinical effort, but Wenger would have been furious with how easily Newcastle carved open his defence.
Calum Chambers could have restored Arsenal’s lead before the interval, but the defender shot wide from Mustafi’s knock down.
Ritchie tested Cech before 18-year-old Arsenal midfielder Joe Willock’s poor finish wasted an opportunity to mark his Premier League debut with a goal.
? “The first thing I want to do is congratulate everyone here at the club… every fan, every player and every member of staff. This is a massive achievement.” #NUFC pic.twitter.com/b0Dzk4o2GO
— Newcastle United FC (@NUFC) April 15, 2018
Iwobi lashed narrowly wide from long-range as Arsenal chased their first away point of 2018.
But it was Newcastle who landed the knockout blow in the 68th minute.
More sloppy Arsenal defending let in Islam Slimani and his header was flicked on by Perez to Ritchie, who beat Cech from close-range.
Ritchie clearly saves his goals for the big occasion, having scored the winner against Manchester United in February.
Kenedy, on loan from Chelsea, came close to putting the result beyond doubt with a looping effort that hit the crossbar with Cech beaten.
Lacazette should have equalised in the closing stages, but he shot into the side-netting.