Shkodran Mustafi opened the scoring in the first half, before Pierre Emerick-Aubameyang doubled Arsenal's advantage.
Petr Cech then saved a penalty from Troy Deeney minutes after, as Henrikh Mkhitaryan was on hand to finish things off with the match reaching its conclusion.
Mustafi heads Arsenal in front with Ozil pulling the strings
Given Arsenal's recent struggles a quick start was something they required against Watford, and with Mustafi's opener they got exactly that.
With just eight minutes on the clock Mesut Ozil swung in a free kick from the left, and Mustafi was there to head Arsenal in front. The German was left relatively unchallenged as he was able to bag Arsenal's 1000th Premier League goal at home.
That assist for Ozil was meanwhile his 50th in the Premier League, the fastest player to reach that landmark. However he could have added to that tally, and even had a goal himself.
The German unleashed Aubameyang inside the opening exchanges but Orestis Karnezis came out to deny the Gabonese striker one-on-one.
Another chance was presented to Aubameyang in the first half, with Sead Kolasinac driving the ball in from the left, which the former couldn't quite make proper contact with at the back post.
Ozil had an excellent opportunity to put the Gunners 2-0 ahead before the break. He collected the ball inside the area and just as he looked to stroke the ball home Karnezis made a brilliant stop.
Hornets threaten to equalise
The Gunners were sloppy in midfield and gifting the ball away gave Watford opportunities, just as it had to Brighton a week previously.
Abdoulaye Doucoure tested Cech minutes after the goal, whilst Richarlison also forced a save from Cech with a free-kick.
His save however only went as far as Roberto Pereyra but he blazed the rebound over when it looked easier to score.
Richarlison also came close as the first half drew to a close. Kiko Femenia drove to the byline and then dinked in a cross which the Brazilian got his head to but was denied by Cech once more.
Frantic second half period
Within the space of a few second half minutes Arsenal put themselves 2-0 in front and Watford missed a penalty.
Mkhitaryan who up until the hour mark had had a poor game, was able to slip in Aubameyang. He had threatened to get in behind for large parts of the match and was able to finally do so here, rounding Karnezis before slotting home the Gunners second of the game.
Moments later Watford were awarded with a penalty. Pereyra ran at Ainsley Maitland-Niles and was then clumsily brought down by the young full-back just inside the area.
Up stepped Deeney but he saw his spot kick saved as Cech dived slightly to his right to save his first penalty for the club.
It was a rather ironic moment for the Hornets' skipper who accused Arsenal of lacking cojones following Watford's victory over them earlier in the season.
Arsenal could have had a penalty of their own shortly after, as Adrian Mariappa clattered into Mkhitaryan and brought the Armenian down just as he had released the ball. Unfortunately for the Gunners nothing was given.
Arsenal wrap things up
As the game approached the final ten minutes Arsenal added a third to seal the win. Ozil found the ball on the left and then teased a ball into the area. Karnezis palmed the ball out but only as far as Aubameyang.
He then teed up Mkhitaryan who fired an effort through Watford's Greek 'keeper to score his second in as many games for the club.
Four minutes from time substitute Danny Welbeck almost made it four. Jack Wilshere played him in but the forward's goal bound shot was saved by Karnezis.
There was a late Watford chance for Sebastian Prodl but he put an effort high and wide as Cech was able to hold on for a 200th Premier League clean sheet.