Roy Keane still rates Arsenal as the biggest threat to Manchester United despite Chelsea's mammoth spending spree.
Keane believes that the Gunners will be the main challengers in the Barclaycard Premiership once more, especially now they have tied down Patrick Vieira and Robert Pires to new contracts.
The Irish midfielder said: "Arsenal are still our main rivals. They have an excellent manager and some top players. "We saw again in the Community Shield that there is not a lot between us so obviously they are going to be our biggest threat.
"They have probably had a stronger squad than us over the last year or two and getting Robert Pires and Patrick Vieira to sign new contracts was probably more important than buying new players as far as Arsenal are concerned."
Keane accepts that Chelsea have become stronger through the players bought by owner Roman Abramovich's millions, but warned that that does not guarantee success.
He added: "Sometimes you can go out and buy players just so the sake of buying them. Then again, I have a lot of respect for their manager, I think he is an excellent manager, but they are a quality team anyway and they will no doubt be stronger for it, and I think they will be there or thereabouts.
"I'm not interested in other clubs really. They have obviously bought a lot of players and are hoping to win the championship, but all I am worried about is United," he told the club's official website, www.manutd.com.
Meanwhile manager Alex Ferguson has confirmed that Keane will be used as an emergency central defender by this season.
The United manager intends to use Keane along with fellow midfielder Djemba-Djemba in his back-line after failing to sign defensive cover during the close season.
"Defensively we could still have a problem. We've got a good back four of Gary Neville, Mikael Silvestre, Rio and John O'Shea," Ferguson told the club's official magazine.
"Then I think Djemba-Djemba can play at right back as I've seen him perform there before and he did very, very well. Roy can also play centre half."
Keane played as a defender for a whole season at previous club Nottingham Forest and also featured successfully in the position against Juventus in the Champions League last year.