Ronaldo scored in the 10th and 13th minutes to take his season tally to 27, and lift the defending champion ahead of Arsenal on goal difference.

Third-place Chelsea stretched its record unbeaten streak at home in the league to 75 games with a 1-0 win over Reading, Tottenham drew 0-0 at fourth-place Everton, Manchester City drew 1-1 at bottom club Derby, and Liverpool lost 1-0 at West Ham.

United and Arsenal, which beat Newcastle 3-0 on Tuesday, are tied on 57 points, four more than Chelsea and 14 more than Everton.

Manchester City joined fifth-place Aston Villa on 41 points, and record 18-time English champion Liverpool fell back to sixth, 17 points off the pace.

'Always to lose is a bad thing for us, but especially this type of game,' Liverpool manager Rafa Benitez said. 'We started really well and also the second half we were creating clear chances.

Ronaldo opened the scoring at Old Trafford from a pass by fellow Portugal winger Nani, then curled in a free kick past goalkeeper David James, who was making his 500th career appearance in the Premier League.

United dominated the match, with defender Rio Ferdinand regularly breaking forward in an attempt to bolster the attack, and Nani almost scoring late with a long-range shot.

Chelsea stayed in strong contention for the title after Germany midfielder Michael Ballack scored at Stamford Bridge when he headed in a cross from Paulo Ferreira in the 33rd.

Chelsea equalled its club record of nine straight wins in all competitions. The previous record was set under Jose Mourinho two years ago when Chelsea was on its way to a second straight Premier League title.

Liverpool seemed set for a fifth straight league draw until Jamie Carragher fouled West Ham midfielder Fredrik Ljungberg in the area, giving away a 90th-minute penalty.

Midfielder Mark Noble hit the ball in to make the result even more damaging to Liverpool's season and Benitez's hopes of being in charge for the next.

'Today we deserved to win but you cannot change the result,' Benitez said.

Everton moved just three points clear of local rival Liverpool when it was held to a scoreless draw by Tottenham, which had not drawn 0-0 in its last 64 matches.

Spurs' defence was marshalled by England international Jonathan Woodgate on debut, while Andrew Johnson missed the home side's best chance with a shot that Tottenham goalkeeper Radek Cerny saved.

Although Derby was denied a second win of the season by Daniel Sturridge's 63rd-minute equaliser for Manchester City, the last-place side was still able to celebrate its first point at home since September. -- AP