Trailing 2-0 from the first leg of the last 16 tie in north London last month, Arsenal slumped to a 3-1 loss by the Catalan side at Camp Nou as Lionel Messi, Luis Suarez and Neymar all found the net.
Arsenal have faced plenty of criticism in recent weeks for their below-par form, with the Gunners now having won just one of their last eight games in all competitions.
And former Manchester United midfielder Keane did not hold back when delivering his assessment of Arsenal’s current situation.
Speaking to ITV Sport on Wednesday night, Keane said: “They’ve got a weak group of players, who can’t seem to lift themselves for certain games.
“A lot of pressure seems to have got to them over the past few months. For players at Arsenal Football Club, if you can’t deal with the pressure, well you shouldn’t be there.”
He continued: “They seem to have a lack of characters there. Technically they are very good players but where are the leaders of the group, to get a grip of these players when they don’t seem up for it?
“Clubs are obsessed with recruitment. They’re looking at technique and fitness levels, but where are the characters?
“There seems to be a weakness running through the whole club.”
Arsenal, who are 11 points behind Leicester in the Premier League, now turn their attentions back to the top flight and their trip to Everton on Saturday lunchtime.
The Gunners have not won the Premier League title since 2004.
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