Martin O'Neill and Chris Sutton made a memorable return to the place where they launched their Celtic careers as the visitors produced some festive fireworks to stun sad Dundee United.

Back in July, O'Neill enjoyed a winning start to his Parkhead career with his first signing Chris Sutton scoring the winner and Henrik Larsson adding the other in a 2-1 victory.

And today the dynamic duo came back to haunt the Premier League basement club with the goals that gift-wrapped the maximum Christmas points for the second time in the space of three days. There are now 53 points between United and the league leaders.

Celtic have not looked back since the opening day and lost just once in the SPL in that time as they have stepped up their crusade towards the Premier League championship.

But they have also made huge strides forward in terms of personnel, quality and confidence and coupled with the presents they received from United they comfortably wrapped up the points that keeps them well clear at the top of the table.

In contrast United's season has gone from bad to worse and their defences' lack of awareness and inability to pick up opponents made sure that they were unable to produce the kind of display that saw them hold Rangers recently.

The visitors looked in the festive mood from the off with Sutton, Larsson, Didier Agathe and Bobby Petta all causing all kinds of problems.

Petta shrugged off the close attentions of McQuillan and Danny Griffin in the fourth minute before lashing a shot over Alan Combe's crossbar to give the home side an early warning.

A minute later and United midfielder Hasney Aljofree became the first name in Hugh Dallas' notebook after a foul on Neil Lennon and then for a deliberate trip on Stilian Petrov.

Larsson then tried to catch Combe unawares with a free-kick in the eighth minute from a wide position just outside the box, but the keeper comfortably gathered despite a deflection off the United wall.

But United broke with pace and promise on the break and Celtic were let off the hook in the 13th minute.

Easton flighted the ball into the areas and Jim Hamilton got up to head on target which Celtic goalkeeper Robert Douglas did well to stretch and touch the ball around the post.

Larsson was handed the best early chance in the 17th minute when David Partridge let Douglas' clearance bounce and Larsson hit a right-foot shot from just inside the box that Combe did well to save.

But the goal Celtic had been threatening finally arrived in the 23rd minute and it came from the penalty spot after Aljofree was judged to have brought Larsson down in the box.

The Swedish international striker stepped up himself to blast the ball low and the pace took it past Combe and into the net for his 28th goal of the season.

Partridge then became the next United man to receive a yellow card on the half-hour which was brandished for persistent fouling and the home side were starting to feel the pressure.

Sutton should have opened up his account in the 32nd minute when Ramon Vega picked him out in acres of space at the far post, but the £6million man somehow headed wide.

Sutton, however, made amends just two minutes later when Petta showed a great burst of pace to leave the United defence in his wake before sliding the ball across the face of goal for Sutton to side-foot home from close range.

Former Rangers man Charlie Miller was running a gauntlet of abuse from the travelling Celtic support and he too was shown the yellow card for a reckless late tackle on McNamara.

The visitors were threatening to run riot and they almost added a third in the 38th minute when Agathe skipped past the challenge of Aljofree before finding Larsson whose volley was well saved by Combe.

Celtic, nevertheless, were refusing to show any Christmas spirit to their opponents and in the 41st minute they wrapped up the points when Sutton rose to head Lennon's free-kick past Combe and into the top corner.

In true title fashion Celtic refused to relax and three minute after the break Petrov fired just wide after Larsson had teed the ball up for him to try his luck from just outside the box.

Larsson was causing all kinds of problems with his running off Sutton and in the 56th minute he hit a powerful right-foot shot from 20 yards that Easton deflected just wide.

But in a rare venture into the visitors' half United went close when striker Steven Thompson burst into the box in the 63rd minute before blazing just over the bar.

The travelling green and white army that had braved the snow and freezing conditions were warmed up further in the 73rd minute when Petrov got in on the act as he side-footed home Agathe's cross-come-shot.

O'Neill was clearly delighted and his own contribution to the party atmosphere was to bring off Larsson, Petrov and Petta and introduced Tommy Johnson, Jamie Smith and Lubo Moravcik in a triple substitution.

For the first time this season the Celtic supporters were heard to sing the words "are you gonna believe us we're going to win the league" and on this showing nobody is going to argue with them.

Dundee Utd: Combe, De Vos, Griffin (McCracken 73), Partridge, McQuillan (Davidson 68), Buchan, Miller, Easton, Aljofree, Hamilton (Winters 75), Thompson.

Subs Not Used: Heaney, Gallacher.

Booked: Aljofree, Partridge, Miller.

Celtic: Douglas, Mjallby, Vega, Valgaeren, Agathe, McNamara, Lennon, Petrov (Johnson 79), Petta (Smith 79), Larsson (Moravcik 79), Sutton.

Subs Not Used: Gould, Boyd.

Goals: Larsson 22 pen, Sutton 33, 40, Petrov 72.

Att: 12,306

Ref: H Dallas (Scotland).