Arsenal challenge gaining momentum after win over Everton

By Mike Collett LONDON (Reuters) - Arsenal became the third team to top the Premier League this season after beating Everton 2-1 on Saturday but even if their stay is a short one, there seems little doubt they will remain serious title contenders. Manchester City have led from the opening day, apart from one week when Manchester United moved to the summit, and Manuel Pellegrini's men can regain first position by sinking their neighbours at Old Trafford on Sunday. United could also go joint top b