The Gunners have been installed as the favourites to lift the top-flight trophy in May after their impressive 2-1 win over title rivals Manchester City at Emirates Stadium on Monday night.
Arsenal head into their trip to Southampton on Boxing Day in second place in the Premier League table and two points behind high-flying Leicester City.
And former Arsenal man Merson feels that the Gunners have not had a better chance of winning the title in many years.
Merson wrote in his column for the Daily Star: “Arsenal are favourites for the title now – and rightly so.
“Manchester City were outstanding against them for half an hour but still never looked like scoring, and after that Arsenal picked their pocket.
“Arsenal will never have a better chance to lift the title. If Arsene Wenger doesn’t win it this season he has to go.
“They should take nine points from their next three games and prove themselves. They’re at Southampton [on Boxing Day], who have been atrocious the last few months.
“If Arsenal don’t take maximum points from these three games then beating City will count for nothing. It will have been meaningless.”
Arsenal have responded to their disappointing opening-day defeat by West Ham United to string together a series of positive results to keep them in the hunt for the title.
The Gunners are through to the last 16 of the Champions League, where they will face Barcelona in the new year.
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