The chances of lightning striking twice was unlikely before kick-off and so it proved as Arsenal avenged their FA Cup quarter-final defeat by beating Watford 4-0 in the Premier League at the Emirates Stadium this afternoon.

Although this was the Hornets’ biggest loss of the season and getting beating by Arsene Wenger’s team is not a reason for concern in itself, this was a fourth successive top-flight defeat for Quique Sanchez Flores’ men and they have now scored just once in their last five league outings.

Unlike the fifth round tie when Arsenal failed to take their early chances, this time they were in front after just four minutes when Alexis Sanchez scored after Heurelho Gomes kept out his header.

Wenger’s side then threatened to put the game to bed before it had really started as Alex Iwobi and Danny Welbeck went close to doubling their side’s advantage.

The Hornets did start to ask a few questions in the final third around the 30-yard mark, but any encouragement quickly subsided when Iwobi finished off an incisive move involving Francis Conquelin and Sanchez to make it 2-0 at the break.

If there were any lingering doubts about the destiny of the points, they were put to bed within three minutes of the start of the second half as former Hornets loanee Hector Bellerin saw his shot wickedly deflected past Gomes off Ben Watson.

Arsenal could have scored more, but became increasingly content to sit on their lot, while the closest their opponents came to a consolation was when Troy Deeney forced David Ospina into a good stop to keep out his shot on the turn.

The Hornets did have their best spell of the match after that opportunity though, only for Arsenal to add a late fourth through substitute Theo Walcott.

Flores made three changes to the side that disappointed for the most part in the 2-1 home defeat against Stoke City before the international break.

Sebastian Prodl was preferred to Miguel Britos in defence, there was no surprise that Watson returned, while Almen Abdi also got the nod and made his 100th start for the Hornets in all competitions. Jose Manuel Jurado joined Britos among the replacements who also included Steven Berghuis, but Valon Behrami was not involved.

Despite having Petr Cech available again after a five-game injury lay-off, Wenger opted to keep faith with the same starting line-up that won 2-0 at Everton in the Gunners’ last outing.

There was no surprise that Arsenal had plenty of the ball from the outset and they almost created their first opening in the third minute when Prodl glanced a Sanchez cross away from the head of Welbeck.

But it took the home side only another 90 seconds to make the breakthrough.

Abdi’s attempted clearance from near the corner flag was headed down by Nacho Monreal to Iwobi, who had the time to come inside before clipping a fine cross over from the left which Sanchez met with a downward header. Heurelho Gomes did very well to to keep it out after diving to his right but the rebound fell perfectly for Sanchez to lift the ball into a largely unguarded net and make it 1-0.

The Chile star created another chance soon after, playing in a cross from the right from close to the byline but Monreal was unable to keep his header down.

The largely one-way traffic continued with Welbeck scuffing a shot through to Gomes after Mesut Ozil and Sanchez had broken at pace after the Hornets had given the ball away. The Watford keeper then needed to go full length to tip over an Iwobi shot before Welbeck saw his attempted right-footed finish deflected narrowly wide of Gomes’ left-hand post following Ozil’s cut back from the right.

Having been firmly on the back foot, Watford had their first sight of goal in the 19th minute when Deeney headed down an Allan Nyom cross from the right, but Ospina was untroubled.

It was soon all handed to the defensive pumps again though for the visitors when a well-struck Coquelin shot was blocked after some intricate build-up play with Ozil and Sanchez once again at the heart.

Gomes was called into action again in the 24th minute to drop to his right to push away a Sanchez free-kick from around 25 yards which he got up and over the wall but not far enough away from the Hornets keeper to really extend him.

The visitors though, were getting into the game more as the opening period progressed and on more than one occasion around the half-an-hour mark were only a final pass or a favourable bounce away from Odion Ighalo having a clear sight of goal.

There were some reasons to be encouraged from a Hornets perspective but any growing optimism was snuffed out in the 38th minute when the Gunners doubled their lead.

A superb angled pass from Coquelin took out the Watford defence and put Sanchez in behind and he cut the ball across for Iwobi to fire a first-time finish from around ten yards past the helpless Gomes.

Flores made a change three minutes later as Ikechi Anya replaced Etienne Capoue, who looked to be limping as he left the pitch but had also been culpable for the goal to an extent by failing to track Sanchez.

A second change followed at the start of the second half as Nordin Amrabat replaced Ighalo but within three minutes of the restart the Hornets were three down.

Sanchez was again heavily involved with a cross from the right which Nyom headed away but only as far as Bellerin, whose first-time effort took a wicked deflection off Watson and wrong-footed Gomes.

And 3-0 almost became 4-0 within two minutes as Iwobi was released in the penalty area and his shot rebounded back out off the crossbar, but Ozil was unable to get his foot around the follow-up.

Arsenal were rampant and only a good blocking save from Gomes prevented Ozil from getting on the scoresheet before the keeper had to go to ground again to keep out a shot from Sanchez.

However, the Hornets did have a chance to reduce the deficit in the 56th minute when Deeney pulled away at the far post to head a Watson free-kick from the right back into the danger zone, but Prodl’s goal-bound header was headed away by Monreal from just in front of the target and then Nathan Ake dragged another shot wide.

After Olivier Giroud had replaced Welbeck and Adlene Guedioura came on for Abdi Watford had another chance when Ake played a low ball in from the left and Deeney used his body to turn Laurent Koscielny before hitting a right-footed curler which Ospina dived to pluck out of the air.

Gomes held a Giroud header from a corner and Walcott replaced Iwobi, but the visitors continued to have a reasonable spell in the opposition half without really threatening to trouble Ospina.

The Hornets continued to plug away and with six minutes remaining Guedioura saw his 25-yard daisy-cutter deflected narrowly wide after he had been fouled by Mohamed Elneny. Moments later, the Algerian cut in off the left but this time dragged a shot wide of the near post.

Another threat of an opening came and went for the Hornets went Amrabat clipped a ball to the far post where Anya, who was only eight yards out, opted to try and head it back to Deeney rather than take it on himself and Coquelin was able to dive to head it away from the Watford skipper.

But having offered comparatively little in the last third for a period of time, Arsenal added a fourth in the last minute of normal time when Campbell took on and beat Nyom before playing the ball across for fellow substitute Walcott to convert past Gomes from close range.

Arsenal: Ospina; Bellerin, Gabriel, Koscielny, Monreal; Coquelin, Elneny; Sanchez (Campbell 79), Ozil, Iwobi (Walcott 73); Welbeck (Giroud 68). Not used: Cech, Gibbs, Mertesacker, Chambers.

Watford: Gomes; Nyom, Prodl, Cathcart, Ake; Suarez, Watson, Capoue (Anya 41); Abdi (Guedioura 68), Deeney; Ighalo (Amrabat 46). Not used: Pantilimon, Britos, Jurado, Berghuis.

Bookings: Nyom for a foul on Ozil (61); Elneny for a foul on Guedioura (84).

Attendance: 59,981 (2,956 away fans).

Referee: Anthony Taylor.