The north London side twice came from behind to lead at Anfield thanks to goals from Aaron Ramsey and Olivier Giroud in a thrilling game on Merseyside.
However, Arsenal were unable to hold on for victory and were pegged back in stoppage time when substitute Joe Allen finished from close range.
The result allowed Leicester City to move level on points with the Gunners, who are top of the table on goal difference heading into Sunday’s trip to Stoke City.
And Merson admits that he was baffled by Arsene Wenger’s decision to take off Mesut Ozil and bring on Mikel Arteta in the second half at Anfield.
Speaking on Sky Sports News HQ on Thursday morning, Merson said: “When they’re winning 3-2 with not very long to go, it was a bad draw. I didn’t think they were great. It was a good game but bad defending both ways.
“They started off poorly and to go in front… they should have held on. I thought Arsene Wenger’s substitution wasn’t very good – he took off Ozil and brought on Arteta and I thought at 3-2 he should probably have put another forward on because they’re chasing the game and then Arsenal can pick them off.
“I just think Arsenal played into their hands and that’s where they got the draw from in my opinion.”
Arsenal are aiming to win their first Premier League title since 2004 this season.
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