Manchester United manager Alex Ferguson said on Friday that he expected Chelsea to challenge for United's Premier League crown, despite the departure of Jose Mourinho.
Chelsea's first game under Mourinho's successor, Avram Grant, ended with a 2-0 defeat at Old Trafford last Sunday, dropping them to sixth in the table, three points and four places behind United.
But Ferguson believes the quality of Chelsea's squad means they cannot be written off in the championship race.
"They got a good result on Wednesday, 4-0 away from home (at Hull City in the League Cup). They played a strong team. I think Avram Grant was keen to get a win under his belt and I think that will help him no end," Ferguson told a news conference.
"I don't think you can dismiss Chelsea. How could you with the players they've got?"
Arsenal lead the table after a bright start to the season which hints at a renewal of their battle with United which dominated the league before Mourinho led Chelsea to the title in 2005 and 2006.
"Their form has been very good. They have laid down a marker. It's going to be an interesting league," Ferguson added.
United's next test comes at Birmingham City on Saturday with Ferguson pleased at his side's progress following a run of 1-0 wins before scoring two for the first time this season against Chelsea.
"Yes we would like to score more goals...but the performance levels have been very good," said Ferguson, who pointed to absences for Wayne Rooney, Cristiano Ronaldo and Louis Saha as mitigating factors in the relatively low goals tally.
Midfielder Owen Hargreaves may return on the bench following a thigh injury which has kept him out of United's last four games, although a mid-week return in Champions League may be more likely.
His England team mate defender Gary Neville is expected to play in a practice match next week as he continues his recovery from calf and thigh injuries.