Victory will put 12 points between them and their closest rivals, second placed Cardiff City.
And if Wigan can overcome struggling Colchester, Swindon and Mansfield Town later this month, they will almost certainly be guaranteed at least a play-off spot.
Mitchell says they are determined to put their 3-0 FA Cup defeat by Stoke behind them when they take to the pitch at Ashton Gate.
The 22-year-old said: "We would love to have progressed in the Cup but we're now concentrating on the match in hand, against Bristol City.
"They are right at our heels in the league and so we feel it is important that we come away with a win."
The former Manchester City trainee has been ever-present for Latics this season, having earned a professional contract in the summer.
He started in midfield alongside Jason Jarrett for their Cup clash against Stoke, but is likely to lose his starting spot to the outstanding Tony Dinning, who is expected to return after a slight back injury.
And Mitchell insists the team's morale has not been affected by last Saturday's defeat at the Britannia Stadium.
He said: "The team spirit in the camp is fantastic, with confidence levels high.
"We're out of the cup so the league is now our priority. There's a long way to go but I think we have what it takes to win automatic promotion."
Jewell added: "Bristol are a smashing attacking side, so it should be a great game."
The game is live on Sky Sports 1, kick-off 7.45pm.
The FA have charged Blackburn manager Graeme Souness with "improper conduct and/or insulting language" to match officials during a Worthington Cup game at Wigan last month.
Article from the wigan Evening Post.