The Manchester clubs have already shown they are the best equipped to win the Premier League title this season but their biggest tests are still to come, former England striker Alan Shearer told Reuters.

City top the standings on 19 points after seven games with United just behind them on goal difference, the free-scoring pair five points clear of Tottenham Hotspur in third place after flying starts to the campaign.

"It will be one of the Manchester clubs that will win," Shearer, the Premier League's record scorer with 260 goals, said in an interview.

"They have both got two top managers in Pep Guardiola and Jose Mourinho, who are used to winning trophies. City didn't hire Guardiola to win the League Cup. They hired him to win the Premier League and the Champions League.

"United did the same and won two trophies already under Mourinho last season. They will be looking to win bigger things this year."