Watford came from behind to hold Arsenal at home despite taking an early lead in the first half.
Pereyra scored from the spot for Watford with ten minutes remaining to salvage a crucial point at Sanchez Flores despite holding the bottom position.
Arsenal scored in the 21st minute through Pierre-Emerick Aubameyang after picking a pass from teammate Sead Kolasinac.
Aubameyang doubled the lead ten minutes later thanks to a typical gunner break and passes sending them ahead in the first half.
The draw sees Unai Emery’s boys settle position seven with eight points behind the likes of Chelsea, Manchester United and Leicester on goal difference.
Defensive issues ruined the gunner’s chances of coming up victorious as midfielder Matteo Guendouzi lost possession twice to the home team.
Sokratis made a defensive blunder allowing Cleverly take possession in the 53rd minute before sending it past Bernd Leno.
Etienne Capoue had the same opportunity as Cleverly five minutes later but failed to convert the ball past Leno.
Former Chelsea defender David Luiz came in as a substitute to provide additional defensive but he instead committed a blunder.
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In the 80th minute, the Brazilian brought down Pereyra inside the penalty box who stepped up to send it at the back of the net.
In another match of the day, Bournemouth humiliated Everton beating them three goals to one.
Wilson of Bournemouth scored twice as Calvert-Lewis scored the only goal of the game for Everton in the 44th minute.
Both teams are tied on seven points but separated on goal difference.