Gael Clichy admits Arsenal's players already had Thomas Vermaelen's card marked before his arrival this season.
The former Ajax defender has been outstanding in the opening weeks of the season and fullback Clichy recalled: "I remember an argument between him and Robin van Persie during a European match two years ago because he was marking aggressively. That's necessary.
"To be a defender, you kind of need that in your game and he certainly has it."
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