Tom Cleverley grabbed a last gasp winner to hand Watford a dramatic win over Arsenal and jump up to fourth in the table.
Per Mertersacker gave the Gunners the lead but the Hornets would not lie down.
Richarlison went over after minimal contact from Hector Bellerin and controversially won the penalty.
Troy Deeney buried the penalty to set up a tense finish at Vicarage Road and after a penalty area scrap, Cleverley followed up a rebound to drive home the winner.
Arsenal
Cech 6
Little to do apart from pick ball out from net for penalty
Koscielny 7
Arsenal always look more assured at the back with the Frenchman
Mertesacker 7
First Premier League start for 532 days crowned with goal
Monreal 6
Always a steady performer in the Arsenal backline
Bellerin 6
Gave away soft penalty with ill-advised challenge
Elneny 6
Got forward to fire over first-half shot. Hard worker
Xhaka 7
Good deadball delivery. Increasingly authoratative in middle
Kolasinac 7
A real positive for the Gunners this season. Adds steel
Iwobi 7
Always busy and available to get on the ball
Welbeck 6
Played behind central striker. Replaced after an hour by Ozil
Lacazette 5
Has yet to score for Arsenal away. One touch in Watford box
Subs
Ozil/Welbeck 60Giroud/Lacazette 68Holding/Koscielny 84
Watford
Gomes 8
Powerless to stop goal. Good saves from Iwobi and Ozil.
Mariappa 6
Sacrificed late on as Hornets pushed for the equaliser
Kabasele 7
Composed display from the Belgium centre-back.
Britos 6
Quiet game on his first appearance since stupid red card against Brighton
Femenia 6
Spent more time defending than going forward from wing-back
Pereyra 7
Did Monreal with superb turn in the first half
Cleverley 7
Saw a lot of the ball early before scoring late winner
Doucoure 6
French midfielder is a big physical presence in the middle
Holebas 7
Great first half tackle to deny Welbeck in the Watford box
Richarlison 7
A £13 million paid to Fluminense is a bargain in the modern market
Gray 6
Watford front man starved of proper service. Replaced
Subs
Deeney/Gray 62Carrillo/Mariappa 62Capoue/Pereyra