John Hartson ended his recent goal drought with a rejuvenated hat-trick at Almondvale tonight as the Bank of Scotland Premier League champions snatched back the initiative from Rangers in an unpredictable title run-in.

Celtic's top-scorer has been in the shadows of countryman Craig Bellamy in recent weeks having failed to hit the net in his four previous matches.

But while Rangers were last night left to rue missed chances after an unexpected defeat at Ibrox to Dundee United, who stay one point above Livingston with six games left, Hartson rediscovered his goalscoring touch to stretch his season's goal tally to 27.

Stanislav Varga also pounced in the dying seconds as Celtic also moved to within just one goal of their arch-rivals.

As a result of last night's shock scoreline, Celtic manager Martin O'Neill opted to name an unchanged line-up from that which booked the Tennent's Scottish Cup holders' return to the final with victory over Hearts at Hampden Park on Sunday.

Richard Gough would have been more stunned than many at his former club's failure to beat his relegation rivals and he chose to make four changes from the side which drew with Dunfermline with Hassan Kachloul, Oscar Rubio, Gustave Bahoken and Derek Lilley in for Colin McMenamin, James McPake, Robert Snodgrass and Craig Easton.

Celtic struggled to get going early on and watching Rangers fans could be forgiven for thinking about another tale of the unexpected.

Bellamy was furious with Alan Thompson in the 16th minute when he played the ball up to his team-mate but never got the return pass as he overlapped.

Burton O'Brien scored twice in the 4-2 home defeat to Celtic in October but the midfielder blazed a 25-yard left-foot shot over the crossbar in the 17th minute.

But David McNamee put his side in desperate trouble five minutes later when he won a tackle and the inadvertently passed the ball back into the path of Bellamy.

The on-loan striker was expected to hit the net with just the goalkeeper to beat but McKenzie stood up well and saved his right-foot shot with his left boot.

Thompson was booked moments later for a mistimed tackle on Kachloul but the game had finally livened up after a poor start.

McNamee became the first player booked for the home side in the 31st minute when referee Mike McCurry took action for a bad challenge on Stanislav Varga.

But Livingston gave watching Rangers fans some hope that they too could spring another surprise in gripping title race in the 31st minute.

Gabor Vincze played a great ball to the overlapping O'Brien but he blazed his right-foot shot over from 25 yards to let the hesitant Celtic defence off the hook.

Celtic looked set to take the lead just four minutes before the break when Bellamy burst clear and then unselfishly squared the ball to Hartson - but Oscar Rubio got back to block his effort and pick up an injury in the process.

Hartson, however, did score moments later when Bahoken made a major mistake to knock the ball back into the centre of goal, after Jackie McNamara had crossed from the right flank, and the striker swivelled to fire into the back of the net from eight yards.

Bellamy came close to joining his countryman on the scoresheet, 10 minutes after the restart, when he sprinted clear of the Livingston defence and then unleashed a low left-foot drive - but McKenzie again stood up well to save with his feet.

Celtic looked like killing the game off with the pint-sized striker causing the basement club no end of problems with his pace.

But goalkeeper David Marshall needed to be alert at the other end to keep his side ahead with a brilliant acrobatic save.

Jason Dair cut in from the left flank and let fly with a curling right-foot drive which the youngster threw tipped over.

Gough made a change in the 69th minute, bringing on Pascal Nouma for Bahoken - but it had the opposite effect.

Hartson secured their passage to the top of the table in the 75th minute when he stooped at the back post to head Thompson's cross home after a quick Petrov corner.

With usual penalty-taker Sutton going off for Stephane Henchoz, the Welshman completed his hat-trick from the spot with five minutes to go after being barged over by McPake.

Varga also got in on the act in the final seconds, reducing the goal difference by converting at the back post - to inflict more misery on Livingston and put the pressure back on Rangers.

Teams

Livingston McKenzie, McNamee, Rubio (McPake 83), Dorado, Bahoken (Nouma 68), Dair, Deloumeaux, Vincze, O'Brien, Lilley, Kachloul.

Subs Not Used: Meldrum, McMenamin, Snodgrass, Easton, Brittain.

Booked: McNamee.

Celtic Marshall, Valgaeren, Balde (McGeady 88), Varga, McNamara, Petrov, Sutton (Henchoz 77), Lennon, Thompson, Bellamy, Hartson.

Subs Not Used: Hedman, Fernandez, Lambert, Maloney, Wallace.

Booked: Thompson.

Goals: Hartson 43, 75, 86 pen, Varga 90.

Att: 8,750

Ref: M McCurry (Scotland).