LONDON, Dec 31 (Reuters) - Champions Manchester City go into 2013 facing a daunting seven-point deficit on Premier League leaders Manchester United and a testing encounter against stubborn Stoke City on Tuesday. Roberto Mancini's side ended the year which delivered their first Premier League title with a gritty 4-3 triumph over Norwich City, proving their high-profile players also have the mettle for a fight. It is early days in the long title run-in but United, who travel to Wigan Athletic on New Year's Day, are traditionally strong in the second half of the campaign. ... More...