Georgios Samaras scored twice to give Celtic a deserved victory over Rangers that stretched the visitors' lead to four points in the league table.
Rangers were denied a fifth-minute lead when Emilio Izaguirre deflected a Lee McCulloch header off the crossbar.
But Celtic took control after the break and Samaras rounded goalkeeper Allan McGregor to score after 62 minutes.
The second came eight minutes later when Samaras was pulled down by Madjid Bougherra and scored with the penalty.
Reigning champions Rangers responded but could not prevent Celtic claiming their first victory on their Old Firm rivals' patch since December 2008.
And it was revenge for a side beaten 3-1 the last time they met their Glasgow neighbours, at Celtic Park in October.
An emotional day at Ibrox was ensured by an impeccably observed minute's silence to mark the 40th anniversary of the Ibrox disaster that led to the death of 66 people at the Old Firm derby on 2 January 1971.
Led out by famous captains John Greig and Billy McNeill, the respective sides had a chance to become modern legends.
But Celtic fans looking forward to the first sight of Freddie Ljungberg in the green and white hoops were left disappointed as the former Arsenal and Sweden winger had picked up a virus.
Manager Neil Lennon was also without suspended captain Scott Brown and the injured Olivier Kapo, along with striker Daryl Murphy, as he was forced to reshuffle his midfield.
Forrest returned for Celtic as Ness was given his first start
Rangers' Walter Smith also was forced into a change after Steven Naismith failed a fitness test and 19-year-old Jamie Ness was given his first start at the heart of midfield.
It was Rangers' reshuffled pack that exerted early control and almost took the lead after five minutes following a corner won after Ness played a classy cross-field ball to Steven Whittaker.
Vladimir Weiss's cross was flicked on by McCulloch and Celtic left-back Izaguirre managed to head the ball off the line and clear via the underside of the crossbar.
Both sides were playing a 4-4-1-1 formation, with Weiss and Paddy McCourt playing behind their respective strikers, and it was the latter who almost proved to have the greater influence despite the more evident trickery of the Slovakian.
The Northern Irishman's fine through ball into the penalty box found James Forrest, who had come into the side along with Beram Kayal, Charlie Mulgrew and Samaras, and forced a goal-saving tackle from McCulloch.
It was now a more even contest with lone strikers Kenny Miller and Samaras, whose inclusion meant that Anthony Stokes dropped to the bench, being starved of ammunition as the half-time whistle blew.
Samaras set up the best chance of the match within seconds after the break, his flicked header finding McCourt racing into the box, but the winger fired his drive wide of the far post under pressure from David Weir.
Just as Rangers looked to have settled after early Celtic pressure, the visitors took the lead after goalkeeper McGregor sold himself after a long ball over the top of the defence from Joe Ledley found Samaras.
Samaras flicked the ball past McGregor and rolled the ball into the empty net and the Greek was soon celebrating a second.
The striker beat Ness for pace then was clipped by Bougherra's lazy leg as he turned inside the Algeria defender before stepping up to beat McGregor from the penalty spot.
Rangers, so subdued and reliant on aimless high balls until that point, suddenly responded and Sasa Papac sent a low drive just wide of the far post then Bougherra volleyed over from 16 yards.
However, Celtic held out comfortably - and came close again from Ledley and Samaras - to leave Rangers requiring wins in their two games in hand to overtake their rivals at the top of the Scottish Premier League.
BBC Sport - Football - Rangers 0-2 Celtic
Rangers were denied a fifth-minute lead when Emilio Izaguirre deflected a Lee McCulloch header off the crossbar.
But Celtic took control after the break and Samaras rounded goalkeeper Allan McGregor to score after 62 minutes.
The second came eight minutes later when Samaras was pulled down by Madjid Bougherra and scored with the penalty.
Reigning champions Rangers responded but could not prevent Celtic claiming their first victory on their Old Firm rivals' patch since December 2008.
And it was revenge for a side beaten 3-1 the last time they met their Glasgow neighbours, at Celtic Park in October.
An emotional day at Ibrox was ensured by an impeccably observed minute's silence to mark the 40th anniversary of the Ibrox disaster that led to the death of 66 people at the Old Firm derby on 2 January 1971.
Led out by famous captains John Greig and Billy McNeill, the respective sides had a chance to become modern legends.
But Celtic fans looking forward to the first sight of Freddie Ljungberg in the green and white hoops were left disappointed as the former Arsenal and Sweden winger had picked up a virus.
Manager Neil Lennon was also without suspended captain Scott Brown and the injured Olivier Kapo, along with striker Daryl Murphy, as he was forced to reshuffle his midfield.
Forrest returned for Celtic as Ness was given his first start
Rangers' Walter Smith also was forced into a change after Steven Naismith failed a fitness test and 19-year-old Jamie Ness was given his first start at the heart of midfield.
It was Rangers' reshuffled pack that exerted early control and almost took the lead after five minutes following a corner won after Ness played a classy cross-field ball to Steven Whittaker.
Vladimir Weiss's cross was flicked on by McCulloch and Celtic left-back Izaguirre managed to head the ball off the line and clear via the underside of the crossbar.
Both sides were playing a 4-4-1-1 formation, with Weiss and Paddy McCourt playing behind their respective strikers, and it was the latter who almost proved to have the greater influence despite the more evident trickery of the Slovakian.
The Northern Irishman's fine through ball into the penalty box found James Forrest, who had come into the side along with Beram Kayal, Charlie Mulgrew and Samaras, and forced a goal-saving tackle from McCulloch.
It was now a more even contest with lone strikers Kenny Miller and Samaras, whose inclusion meant that Anthony Stokes dropped to the bench, being starved of ammunition as the half-time whistle blew.
Samaras set up the best chance of the match within seconds after the break, his flicked header finding McCourt racing into the box, but the winger fired his drive wide of the far post under pressure from David Weir.
Just as Rangers looked to have settled after early Celtic pressure, the visitors took the lead after goalkeeper McGregor sold himself after a long ball over the top of the defence from Joe Ledley found Samaras.
Samaras flicked the ball past McGregor and rolled the ball into the empty net and the Greek was soon celebrating a second.
The striker beat Ness for pace then was clipped by Bougherra's lazy leg as he turned inside the Algeria defender before stepping up to beat McGregor from the penalty spot.
Rangers, so subdued and reliant on aimless high balls until that point, suddenly responded and Sasa Papac sent a low drive just wide of the far post then Bougherra volleyed over from 16 yards.
However, Celtic held out comfortably - and came close again from Ledley and Samaras - to leave Rangers requiring wins in their two games in hand to overtake their rivals at the top of the Scottish Premier League.
BBC Sport - Football - Rangers 0-2 Celtic
.. i dont think Cha Du-Ri, Ki Sung-Yueng or Biram Kayal will appreciate being linked to the pope
. Though Parkheads gates have always been open to all.
Comment