The prognosticators were right: the Premier League title would come down to Manchester United or Chelsea.

Though Arsenal put up a strong effort to stay in contention, and are still mathematically in the chase, it has come down to leader Manchester United and defending champion Chelsea on Sunday when the two clubs meet at Old Trafford.

While Chelsea have struggled at points throughout the season, and manager Carlo Ancelotti has been subjected to rumors of being sacked, Manchester United have basically been on top of their game for nearly the entire season.

At first, there was a early-season slump for Wayne Rooney, and public discussion of leaving Manchester United -- to which club, nobody knows. But the conversation was out there, and it was causing considerable distraction.

Once all of that was taken care of, Rooney slowly but surely returned to his elite form, and as he's improved so has the swagger of the Red Devils.

After some key injuries, Sir Alex Ferguson finds himself with a healthy club.

The key man for Manchester United will be Nemanja Vidic. The central defender might be the best player in the Premier League, and he will have to keep the Chelsea attack from finding openings.

But the main reason Vidic is important is because of who is most important to Chelsea: Didier Drogba. The Blues can't count on inconsistent Nicolas Anelka, and certainly can't rest on the goal-scoring ability of Fernando Torres, so that means Drogba, who thrives in pressure situations, will be the main scoring threat.

Drogba has only 16 goals in 53 matches, a far lower output than last season when he scored 43 goals in 50 matches.

But the Ivory Coast star has two goals and four assists in his last five matches, and that includes a goal against Manchester United in the Champions League semi-finals.

Vidic is a hard-nosed defender, and has the size to contain Drogba. Vidic is also effective in the air to prevent a goal off a freekick or corner kick.

Manchester United will look to Rooney to provide the offense. After resting this week in the Champions League semi-final, having sat out two matches for suspension, and having a fully healed hamstring, Rooney is in good shape.

Chelsea defender David Luiz, who is still a little raw, may have his hands full with Rooney and Javier Hernandez. The young Mexican star has given defenses fits for his ability to weave through defenders.

The last time the two clubs met in a Premier League match, Chelsea came out ahead 2-1 at Stamford Bridge.

Expect revenge to be on the Red Devils' minds following that defeat, and a victory is certainly probable considering Manchester United have not lost a Premier League match at Old Trafford all season.

This match would be intense even if it didn't have the Premier League title in the balance. Now, with the stakes so high, it will be twice as intense.

Chelsea know a tie will probably not be enough. They need to win, and that means they need to attack. A victory at Old Trafford will require a fantastic effort by the Blues.

Will the defending champs play their best match of the season?