Arsenal have been slammed over their poor start against West Ham United on Sunday.
The Gunners were three goals behind within 32 minutes at the London Stadium, but they did manage a dramatic comeback, drawing 3-3 thanks to two own goals and an Alexandre Lacazette header.
The draw will feel like a win for Mikel Arteta's men, but despite managing to come from behind with an impressive second-half display, former player turned Merson believes the first half collapse is not to be ignored.
“Five players played on Thursday night, so it’s not really that (a hangover from Thursday). It’s unacceptable, you can’t start a Premier League game like that," he told Sky Sports.
"How many times have you seen it this season, where teams just turn up and play like they want?
"You can’t do that and they got punished, but fair play to them for coming back, I can’t talk highly enough about how well they did to come back from three goals down, they showed a lot of spirit.”
He added: "That was Arsenal’s season in 90 minutes. It’s so inconsistent: it’s one minute of being poor and the next minute they’re great and that’s not good enough.
"If you want to be a successful football team, then you’ve got to be consistent. At the moment, it’s like a roller coaster and Mikel has to sort that out if they’re going to be successful next season.”
Fellow pundit Jamie Carragher agreed, claiming the first-half display was as bad as anything rivals Tottenham have produced this season, despite performing poorly, at times.
“It’s been a brilliant week for Arsenal, beating their biggest rivals last weekend, going through in Europe, seeing their biggest rivals go out," said Carragher.
"But I can assure you, this first 33 minutes is as bad as anything Tottenham have produced over the last couple of games.”
