Rangers remained top of the Scottish Premier League on goal difference from Motherwell following a 2-0 win over Aberdeen at Ibrox.
Celtic, who are a point behind their Old Firm rivals, had put the pressure on when Gary Hooper's double secured a 2-0 victory away at St. Mirren.
Rangers got off to a dream start when Steven Davis gave them a 15th-minute lead. Aberdeen, who haven't won at Ibrox since September 1991, improved after the break with Richard Foster hitting the bar with a header.
But Steven Naismith added a second in stoppage time as Ally McCoist celebrated his first win at Ibrox since taking charge.
McCoist said he was happier with the result than the performance. "I spoke to the guys before and after the game and the most important aspect of today was getting three points," the Rangers manager said.
"We did and that's all you can really say because we will play miles better than that in games to go throughout the season."
Aberdeen counterpart Craig Brown couldn't believe his side had lost. "I think we played reasonably well, well enough to get at least a point and maybe even all three points," said Brown.
"We shouldn't have been in the position of having to desperately seek an equaliser towards the end as we had one or two good chances."
Rangers too strong
Rangers looked determined to erase the memory of their European exit to Maribor in midweek and Kyle Lafferty was sent clear by a headed flick on from Nikica Jelavic, but the Northern Irishman saw his shot sail over the bar.
However, Rangers took the lead in an almost carbon copy move in the 15th minute as this time Davis got on the end of Jelavic's clever pass to poke it past David Gonzalez from 12 yards.
Midfielder Edu was inches away from adding a second on the stroke of half-time when he got on the end of Gregg Wylde's excellent delivery from the left but his header bounced just past the post.
Aberdeen improved a lot in the second half and Fraser Fyvie sent a fierce low drive into the arms of the goalkeeper as Aberdeen continued to improve after the break.
Hooper hits two for Celtic
Hooper's double also helped Celtic to recover some pride after crashing out of the UEFA Europa League. Anthony Stokes had the ball in the net in the early stages, but the referee judged him to have fouled Saints defender Marc McAusland beforehand.
However, English striker Hooper opened the scoring in the sixth minute when he played a sharp one-two with Stokes on the edge of the penalty area before keeping his cool to bury the ball past Craig Samson.
Hooper then doubled the Hoops' lead six minutes later when he intercepted a slack pass from Paul McGowan and raced clear to fire a crisp finish into the bottom corner of Samson's net.
St. Mirren piled on the pressure in an attempt to get back into the game, with McGowan nearly making amends for his blunder with a strike that Fraser Forster did well to beat away.
The Buddies continued to try and find a way to break down the Celtic defence in the second half but had goalkeeper Samson to thank for keeping the scoreline down after he made good saves from South Korean Ki Sung-Yeung and James Forrest late on.