The Italian, a £2million summer signing from Arsenal, played his part in Wednesday night's 2-1 Capital One Cup fourth-round victory over Southampton at the Stadium of Light, which handed the Black Cats another home tie against Chelsea in the quarter-finals.
Mannone was included with Republic of Ireland international Westwood still suffering the after-effects of his run-in with Hull defender Paul McShane at the weekend, which left him slightly concussed and prompted his understudy's introduction as a substitute.
However, with Barclays Premier League title contenders City due to head to the north-east on Sunday, he has no intention of stepping aside without a fight.
The 25-year-old Mannone said: "Of course I want to keep my place, that's why I came here.
"I've been hurting on the sidelines, so I was really happy to take my chance on Saturday and do well for the team.
"It was a really good win last night and I was involved in a good performance. I want to push on.
"Obviously it's down to the manager but I'm available for him and I will push as hard as I can in every single training session and every single chance I get out there.
"This manager is very open to performances, he likes to watch the game and he will pick what he thinks is the best side.
"It's not down to me, the manager has an opinion. But hopefully I've done enough to show I can play in this team and I want to push on to be number one. That's why I'm here."
While the League Cup may not be Sunderland's immediate priority - they remain in 19th place in the league table and five points adrift of safety - victory over the Saints represented a significant morale-boost.
Southampton manager Mauricio Pochettino, as has been his habit, made wholesale changes to the side which has enjoyed such an impressive start to the season, retaining only Jay Rodriguez from Saturday's 1-1 draw at Stoke in order to give vital game time to his fringe players.
But ultimately, he was made to pay the price as Sunderland's squad men - opposite number Gus Poyet made seven changes - came out on top.
Rehabilitated full-back Phil Bardsley set the ball rolling after 59 minutes when he stabbed the opening goal past former Black Cats keeper Kelvin Davis from close range after Jozy Altidore's header had been beaten into his path.
And the United States international striker was the provider once again four minutes from time when he fed substitute Sebastian Larsson to wrap up the win.
Southampton defender Maya Yoshida gave the visitors hope when he headed home after an 88th-minute free-kick had been helped into his path, but it all proved too little too late.
It was the Saints' first defeat in nine attempts in all competitions since August and doubled the number of goals they had conceded in the previous eight in one fell swoop.
Indeed, it was the first time their defence had been breached more than once all season.
Their late reply proved a source of frustration for Mannone and his back line, but the smiles were on Sunderland faces as the final whistle sounded.
The keeper said: "We were really down as defenders and me personally because it was two minutes to go and a set-piece again.
"It was a great delivery but we could have done better. But of course, I take the good 88 minutes and if we keep defending like that, then I don't think we are going to concede goals like before.
"We need to start from that base, don't concede first and then when we have the ball, try to create.
"The win has given us a big boost in morale and we need to start from there, go on to the pitch on Sunday and think we can defend and play when we have got the ball."
- Sports & Recreation