The Gunners will be looking to bounce back from a three-game losing run which has left the north London side fighting to salvage their 2015/16 season.
Arsene Wenger’s side suffered a 3-2 defeat by a weakened Manchester United outfit at Old Trafford in the Premier League on Sunday afternoon.
The Gunners are five points behind leaders Leicester City with 11 games remaining in the Premier League title race.
And former Arsenal playmaker Merson explained why it is vital that the north Londoners secure a much-needed win against Swansea.
“I’d say this is probably the biggest game of the season so far for Arsenal,” Merson told Sky Sports.
“Swansea had a kick in the teeth after losing from 1-0 up at Spurs and they are probably the perfect team for Arsenal to play this week because they’re a nice team who won’t kick Arsenal off the pitch.
“Arsenal should win – but if they don’t score in the first 20 minutes, it could get very cagey.”
The Welsh side have already suffered a defeat in north London this week after a 2-1 reversal at Tottenham Hotspur.
The Gunners hosts the Swans on Wednesday night before Wenger’s side travel to their bitter rivals Tottenham in Saturday’s north London derby.
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