The Gunners are sitting five points clear of defending champions Man City ahead of this weekend’s round of fixtures.
Arsenal, who have won 14 of their 17 league games this term, visit north London rivals Tottenham on Sunday, while City face Manchester rivals United at Old Trafford on Saturday.
While Merson has been impressed by Arsenal’s form, he still expects Manchester City to defend the title unless Mikel Arteta’s side take four points from their two games against Pep Guardiola’s team.
Merson believes there is a huge difference between Arsenal and Man City in terms of bench strength, highlighting the fact that Arteta ‘doesn’t seem to trust’ £34m summer signing Vieira.
‘Arsenal have done amazingly but they are a long way off being title contenders, in my opinion,’ Merson told Sky Sports.
‘Just look at that Newcastle game. They couldn’t bring anybody on when they needed to change it.
‘There’s nobody on the bench bar Fabio Vieira, who Mikel Arteta paid £34m for and doesn’t seem to trust.
‘Then, two days after that game, Man City are looking like they might draw against Chelsea, but they just bring on Grealish and Mahrez and one crosses it, one scores.
‘That showed the quality Pep Guardiola has to work with and I just don’t see how Arsenal are going to be able to live with Man City over a period where there are 60-odd points up for grabs.
‘Arsenal would have to take four points off Man City in those two games to have absolutely any chance of winning it. Otherwise, I just don’t see how Arsenal are going to do it.
‘I think we’re going to see a lot more teams do what Newcastle did because Arsenal have earned the right for that. They are a good team.
‘I go to Stamford Bridge and teams do that every week against Chelsea. It’s only Man City who don’t. Now that’s going to be the same for Arsenal.’
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