The Gunners resume domestic action at Vicarage Road for the late televised kick-off looking to maintain momentum from their demolition of the Red Devils, who were taken apart with three goals inside the first 20 minutes.
Wenger, though, knows that stunning performance will quickly be forgotten should they fail to deliver against the Hornets.
"It can increase the belief and the hunger of the team (to win convincingly)
On the other hand you have to show that you can come in to every game with that focus," said Wenger, who is hoping Alexis Sanchez returns fit from international duty with Chile having been carrying a hip problem.
"The level of champions and people who want to fight at the top is urgency - and urgency is something that keeps you alert, so we know what will be expected of us.
"We have to be conscious that it will be a different game at Watford, but the level of urgency is a big part of success and that is what we work on."
Wenger accepts such little time to regroup following the international break is not ideal, especially with the players having been on a high following the manner of their win over United.
"It was difficult, we separated on a positive vibe
After, the task is to reconnect quickly because everybody goes to their national teams and has different worries," said Wenger.
"The target now is to refocus on what we want to achieve.
"Watford are a very difficult team to play against, so we have to focus to get a positive result on Saturday."
Arsenal's win over United moved them to within two points of Manchester City.
Wenger believes this season's title race could prove to be the most open of recent years and refused to rule out champions Chelsea - already 10 points adrift - mounting a recovery.
"At the moment the top eight can mathematically compete," said Wenger.
"(Realistically), I would say five or six teams (can win the title)."
The Gunners boss added: "(Chelsea) have some ground to make up
Of course when you have many teams in front of you it is difficult to catch up, but they have the quality."
Wenger, though, is not about to lose any sleep over the challenges ahead for Jose Mourinho's squad if the Blues are to haul themselves back into contention.
"I don't care too much about that
My worry is about my team and what we can do," said the Gunners boss.
"We are two points behind the league leaders and what all the other teams do is up to them.
"I just want to say mathematically you cannot rule anybody out at the moment."
While there is the small matter of a Champions League showdown with Bayern Munich next Tuesday night, Wenger insists that European tie will have no bearing on how he sets his team up at Vicarage Road.
"Not at all
For me the most important game is Watford," said Wenger, who could have centre-back Laurent Koscielny fit again from a hamstring injury.
"I would say the Premier League is the most important competition for us."
Source : PA
Source: PA