This was a game of two halves, a first half that saw Arsenal race into a two-goal lead following a brace from Pierre-Emerick Aubameyang and a second half that saw characteristic errors from the Arsenal defence that allowed Watford back into the game.
Aubameyang is one of the sharpest strikers in the game and he richly deserved his two first-half goals, he was in the right place at the right time and was at his clinical best.
Watford will no doubt complain about the first goal but Will Hughes went down far too easily under pressure from Dani Ceballos and then Saed Kolasinac showed his speed after picking up the loose ball before feeding Auba who turned beautifully before putting the ball into the left-hand corner of the net.
The second goal involved every Arsenal outfield player before Maitland-Niles slotted the ball to Aubameyang to slip the ball into the open goal.
At this stage, Arsenal was cruising but there were signs that if things were to go wrong it would be because of the defence.
The second half kicked off and what can I say, Watford dominated and peppered the Arsenal goal from the get-go but it was not any brilliance from Watford that brought them back into the game, it was an awful pass from Sokratis to Guendouzi that Gerard Deulofeu intercepted and Tom Cleverley scored from. It was very lazy from Sokratis who deservedly got punished.
After this Arsenal looked scared, their heads dropped and matters were not made any easier when Unai Emery inexplicably brought off Dani Ceballos in the 60th minute for Joe Willock.
Arsenal had a chance on the 70th minute when Pepe found Reiss Nelson, who came on for Guendouzi, on the edge of the area but his shot went straight at the keeper.
But Watford kept up the pressure, especially through Deulofeu and with 15 minutes to go we saw the spectacle of Arsenal deploying spoiling tactics and time-wasting.
Then came the 78th minute and of course, it had to be David Luiz who gives a penalty away which Pereyra duly converted and it was 2-2.
Watford kept the pressure up in search of a winner and boy did they come close a few times, Arsenal literally crumbled, there was no spark, no passion, no guts, Watford, who looked absolutely beaten in the first half played like a top-six team, whereas Arsenal looked like the team at the bottom.
Watford nearly won it at the end and if they had there could have been no complaints from Arsenal.
The post mortem on this game will not be kind for Unai Emery and his men.