The 25-year-old Italian becomes the latest man to accept compatriot Paolo Di Canio's offer of employment on Wearside as the manager moved to replace the departed Simon Mignolet. Mannone, who joined Arsenal from Atalanta as a 17-year-old, has signed a two-year deal for an undisclosed fee, understood to be around £2million.
However, having made just 26 senior appearances in eight years with the Gunners, the former Italy Under-21 international wants regular football, and that means a battle with Republic of Ireland international Westwood. He told the club's official website: "Of course, every player knows they have competition."
Mannone added: "We live in a world of competition. I will work and do my best to be in the first eleven, and then the manager will decide. All I can do is try to show what I am capable of."
Both men have big boots to fill with Belgium international Mignolet having earned a £9million move to Liverpool with consistently excellent performances during his time at the Stadium of Light.
Westwood is desperate to regain his international place with Ireland boss Giovanni Trapattoni having turned to Millwall's David Forde because of his lack of club football, and that will provide him with an added incentive to make the most of Mignolet's departure.
However, Mannone is viewing his arrival on Wearside as a chance to fulfil the potential which persuaded Arsene Wenger to take him to north London, and he is confident Sunderland can give him the platform to do just that.
He said: "The potential [of the club] is incredible. I have come from a big club but to be honest, I don't see any difference in the facilities. From what I can see on my first day, they are brilliant. To have good facilities where you can work and improve is something every club wants to achieve.
"The base is there and I am really happy to be here. I waited a long time for an opportunity like Sunderland, and for me it is a great one. I'm very excited. I am here to work hard and to show what I can do."
Mannone follows Valentin Roberge, Modibo Diakite, Cabral, David Moberg Karlsson and Duncan Watmore into the club with the Black Cats' summer recruitment drive showing little sign of abating.
- Sports & Recreation
- Simon Mignolet
- Paolo Di Canio