The Spanish attacker, who joined the Gunners from Malaga last summer, scored both of his side's goals at the Emirates Stadium to keep them in contention for a place in next season's Champions League.
"You see he takes his chances with his technique and his feeling," centre-back Mertesacker told the club's official website.
"He is the perfect footballer. He has the technique to score goals and that's what we need after losing the last two home games."
Cazorla, 28, has scored 11 goals in all competitions so far this season.