overcame Chelsea in the FA Cup semi-finals over the weekend.
Now Mancini's side will be looking to strengthen their hold on second spot as they try to hold off Arsenal, Chelsea and Tottenham.
Leaders Manchester United restored their advantage at the top of the table to 15 points with a 2-0 win at Stoke, leaving City with virtually no hope of retaining the title.
City midfielder Gareth Barry concedes his club, who won the FA Cup in 2011 before winning the Premier League 2012, must now be competing for silverware every season.
"We knew this (the FA Cup) was the realistic chance of a trophy this year," Barry said. "Where the club is now, you don't really want seasons going past without winning a trophy.
"The FA Cup is a massive one. If we can win that, fantastic.
"Wembley is a fantastic place to come and play. The big players, as we have seen over the last few years, when we come to semi-finals and finals, they generally turn up and do the business.
"Hopefully they can continue that until the final."
Mancini may decide not to risk Spanish forward David Silva, who missed Sunday's semi-final with a hamstring problem.
But City have been boosted by the news that Sergio Aguero will not face retrospective action from the Football Association after catching Chelsea's David Luiz with a two-footed challenge at Wembley.
Defenders Maicon and Micah Richards are City's only other two absentees as they look to extend a fine run that has seen them win seven of their last eight matches.
Wigan know they must improve their miserable record against City, following a run that has seen them lose their last five games against Mancini's side without scoring a goal.
Wigan are in the FA Cup final for the first time in their history, but have slipped into the relegation zone, although they have two games in hand on Sunderland, Stoke and Aston Villa, who they trail by three points.
Roberto Martinez's team are also in their best run of form in the Premier League all season with three wins and just one defeat in their last five outings.
Wigan pulled away from trouble with seven wins from their final nine games last season after avoiding relegation on the final day of the season in 2011 and goalkeeper Ali Al Habsi is sure Martinez's men can manage another escape.
The Oman international said: "We will do it. We will stay in the Premier League.
"The FA Cup won't distract us. Our squad is big enough to cope. We have been in this situation many times, we believe in ourselves and we will be okay.
"We are a small club and we don't have that many fans but they all believe in the team. To reach the FA Cup final for the first time is amazing.
"But I can promise it won't be a distraction. It all has to be done in order, first the league, then the final, then Europe. Brilliant."
With defender Ivan Ramis out for the rest of the season with a knee injury, Martinez is likely to select a similar side to the one that beat Millwall 2-0 on Saturday.