Celtic survived a last-minute penalty scare to claim a nerve-wracking win over Hearts in Glasgow.
It was a full 72 minutes before Victor Wanyama put the hosts ahead with a fine solo strike from the edge the area.
Anthony Stokes had earlier headed a James Forrest cross off the underside of the bar after Hearts' Scott Robinson came close with a long-range effort.
Goalkeeper Fraser Forster kept out an Eggert Jonsson penalty with 60 seconds remaining to hand Celtic a vital win.
The victory puts Celtic back to within four points of Rangers at the top of the Scottish Premier League table, while Hearts hang on to fifth place behind St Johnstone.
Celtic manager Neil Lennon made one enforced change to his side for the match, with defender Adam Matthews ruled out due to an ankle injury and replaced with Charlie Mulgrew.
Hearts made three changes, with Ian Black, Scott Robinson and Ryan Stevenson coming in for Andy Webster, John Sutton and Rudi Skacel.
Celtic dominated the early stages, with Georgios Samaras, Stokes, Gary Hooper and Cha Du-Ri all probing the Hearts defence.
A sterling chance landed at the feet of Hooper in the six yard area, but he toe-poked the ball past goalkeeper Marian Kello's right-hand post.
Moments later, Hooper latched on to a Samaras cut-back from the goal-line, but the ball rebounded off his ankle and rolled into Kello's hands.
As half-time approached, Stokes shot from 25 yards out and warmed the hands of Kello, but Hearts' strategy of limiting Celtic around the penalty area continued to benefit the visitors.
After the break, Hearts gave Celtic a scare with an early free-kick from the boot of Black that Forster edged out for a corner.
Hearts continued to grow in confidence, with a Scott Robinson shot from 30 yards out that inched past Celtic's right-hand post - then Beram Kayal tested Kello at the other end with a low drive from 18 yards.
James Forrest blitzed down the right flank on the hour mark and flighted in a ball that Stokes headed off the Hearts crossbar.
However, Hearts continued to frustrate Celtic's efforts going forward and Robinson earned himself a yellow card for time-wasting when the hosts were preparing to take a free-kick.
Wanyama finally broke the deadlock with a casual strike from the edge of the D in the 72nd minute, blasting into the top left-hand corner of Kello's goal after a Charlie Mulgrew free-kick was deflected out by Adrian Mrowiec.
A free-kick swung in by Ki Sung-Yeung met the head of Samaras in the 76th minute but drifted wide of the mark.
Hearts could have pulled one back following a controversial decision in the final minute when Wanyama was penalised for a challenge inside the area, but Jonsson was thwarted by a fine Forster save from the spot.
Tempers frayed in the three anxious minutes of added time, but Celtic held out to claim the three points.