Per Mertesacker calls on Arsenal strikers to rediscover killer instinct

The Gunners' chances of silverware this season were severely dented by Sunday's FA Cup defeat to Watford

Per Mertesacker insists Arsenal's season is not over - but has called on the club's goalscorers to rediscover their killer instinct.

The Gunners were knocked out of the FA Cup on Sunday afternoon as Watford secured a 2-1 win at the Emirates Stadium to eliminate the holders and book their own place in a Wembley semi-final.

Odion Ighalo ended a personal barren spell in front of goal by putting the Hornets ahead before Adlene Guedioura lashed in a second to send the 12-time winners out - despite Danny Welbeck's late strike setting up a grandstand finish.

The result means Arsenal cannot become the third team to win three successive FA Cup trophies and has seriously dented their chances of silverware of any kind this season.

They now go to Barcelona on Wednesday night looking to overturn a 2-0 home defeat in the first leg of their round of 16 clash with the reigning Champions League holders, and a team at the top of their game.

After that, a tricky trip to Everton in the Barclays Premier League could see Wenger's men more looking over their shoulder rather than up at pace-setters Leicester following a dismal run of two wins in nine league games.

Wenger has been constantly defending both his position as manager and Arsenal's chances for success this season, labelling speculation over his own future as "boring" and "a farce" on separate occasions.

And Mertesacker has backed up his manager's claims - insisting there is still something to fight for despite the latest set-back.

"It is as you can imagine, we are out of the competition and the treble dream is over, that is (the) conclusion of today's game," he said when asked about his disappointment after the game.

"The season is not over. We play in a confident way, we maybe lack that bit at the end.

"What is really important in football, to be successful we need to score. The desire to play together and to be good at a team is there, you can feel that, even if there is a bit of negativity I can understand."

Mertesacker was involved in both of Watford's goals and he failed to clear Nathan Ake's throw-in which Troy Deeney knocked into Ighalo's path before turning his back on Guedioura's rocket.

But the German World Cup winner believes it is at the other end of the pitch where Arsenal's problems lie.

"What we do lack at the moment is we need to score at some point," he added.

"It looks like we play, and play and play until the opposing team scores. That is something we need to work on. We had the opportunities and the possibilities when they were 2-0 up to come back and we kept going.

"You have to give credit because we kept going and created chance after chance, but at the moment we lack that killer instinct.

"We need to work on that if we want to be successful in the Premier League and the Champions League."

While Arsenal look to get their faltering season back on track before it does prove too late, Watford's continues to go from strength the strength.

Having been promoted last season the Hornets had a major summer overhaul, including the appointment of a new manager in Quique Sanchez Flores.

The Spaniard has since galvanised a new-look squad to the point that Watford are looking more and more like securing their Premier League survival - and now he is taking them to Wembley.

Skipper Deeney has praised the strength of the Watford squad - claiming they have "a set of nuts" - and knows all minds cannot now be cast to a first FA Cup semi-final for the club since 2007.

Asked if the team now deserved more credit, Deeney replied: "That would be up the media to change and write the words in a different way.

"In the dressing room we have enough lads with experience and a set of nuts as well, we are not worried what other people say about it at all.

"It is all in-house and what we say stays in-house and it is all fun and it is a great group, not many teams up and down the country could have 25 lads and say all 25 graft away whether in or out of the team."

Deeney was involved on Watford's last Wembley visit - a 1-0 play-off final defeat to Crystal Palace three years ago - and believes the club are in a much better place to deal with the pressures of playing at the iconic stadium this time around.

"That is long gone," he said of the 2013 play-off loss.

"As a club and as a player we weren't ready to go up so it was probably the best thing that happened, I'm a firm believer that everything happens for a reason.

"We will be ready and take the occasion on differently now, we wont be caught up in the fire and everything that goes on beforehand, we will be actually ready for the game."