MANCHESTER (AFP) - Sir Alex Ferguson believes Chelsea still represent one of Manchester United's sternest challengers for the Premier League despite manager Andre Villas-Boas's relative lack of experience. The spotlight has been off Chelsea, who have been challengers for the last seven years, and switched closer to home with Manchester City joining near-neighbours United at the top of the Premier League. But Ferguson says the focus and publicity being away from the Londoners will suit Villas-Boas down to the ground. The top-flights youngest coach would have been boosted by the settling in period as he finds his feet in his new home. And although the 33-year-old former Porto manager faces his biggest challenge yet when he faces Ferguson on Sunday, the Manchester United manager anticipates his side will still be taking on one of their biggest rivals to their crown. At the moment, of course, the two Manchester teams are enjoying the publicity that comes from the predictions that they are going to be involved in the winning of the league.