Alexis Sanchez scored against his old side before Jesse Lingard added a second minutes later.
Both of the goals were assisted by Lukaku, who has been playing on the right tonight.
But Neville, who made nearly 400 appearances for United, made a big accusation on the BBC’s coverage about the Belgian.
In the clip, Match of the Day host Gary Lineker asks the 42-year-old about his former side’s counter-attacking play.
“Two or three passes and it’s got to end in a goal,” Neville replies.
“That’s what Arsenal haven’t done.
“They’ve taken four, five or six passes.
“As soon as Jesse Lingard gets the ball, it’s straight out to Romelu Lukaku.”
And the former midfielder suggested the 25-year-old was not playing by the rules.
“He’s cheating,” Neville adds.
“He’s not going back with the left-back.
“He’s cheating. Next minute it’s a goal.”
“He’s half cheating because he’s thinking about attacking rather than defending”
Lineker and co-pundit Ian Wright then jump on the United legend for his allegation.
“Is cheating the right word,” the host asks.
And Wright snaps back: “He’s being intelligent.”
Stumbling for words, Neville then explains his reasons.
He continued: “If you were a defender and you went forward…”
Lineker tries to interrupt the former midfielder – but Neville is having none of it.
“It’s a tactic,” Neville concludes, speaking over his host.
“He’s half cheating because he’s thinking about attacking rather than defending.”
This comes as Gunners legend Martin Keown was rinsed by United fans for his epic blunder.