The Baggies took a two-goal lead against Arsene Wenger’s side only for the Gunners to battle back to earn a draw, but they still lie five points behind United, who beat Bolton Wanderers thanks to a late Dimitar Berbatov goal.
The Congolese international believes that Sir Alex Ferguson’s side’s greater mental strength will see them pick up more points than Arsenal during the difficult end of season run-in and Mulumbu says last weekend’s results suggest United can grind out enough wins if required.
"I think it will be very hard now for Arsenal. They have dropped a lot of points," he said in The Sun.
"I feel Manchester's team is too solid to let this championship slip. I think the title is already over and that Manchester will win it.
"It comes down to mentality. Manchester are very strong. In a game like Saturday's, I think they could come back and equalise and then win the game. I believe that's what Arsenal is missing a bit.”
The West Brom midfielder believes that United’s experience gives them the edge with Arsenal’s young team yet to taste success.
"I would say that's their downfall," he said. "The youth and the enthusiasm they have but, unfortunately, they do not have the mentality that Manchester possesses.”
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