The opener came not long after. Nketiah picked up possession on the left side, cutting across and curling a shot which deflected in off the far post.
Nketiah found himself in a similar position minutes later, but this time his drilled strike was stopped and held by goalkeeper Daniel Bachmann.
Watford pressed Mikel Arteta’s side tirelessly and got their reward on 40 minutes. Louza stole the ball in the Arsenal box and laid off to Joshua King, who found Zinckernagel in the six-yard box. Although Zinckernagel’s initial effort was blocked, the Dane’s second shot hit the back of the net to bring the Hornets back on level terms.
Soon after, Sarr won the ball in the centre of the park with a committed tackle and played in the goalscorer Zinckernagel, who carried the ball into the final third for another chance. He passed to Louza and the new signing from Nantes tested Bernd Leno in the Arsenal goal, forcing a corner.