Rangers made it seven away wins on the trot, while Celtic slipped further behind their Old Firm rivals.
Rangers maintained the lead at the top of the table with a 2-1 victory at Aberdeen as Ally McCoist's men continued their 100 per cent record on their travel.
The win was overshadowed by a serious-looking injury picked up by Steven Naismith in the first half.
Kyle Lafferty broke the deadlock after 58 minutes with a clinical finish and Nikica Jelavic added a second from the penalty spot 11 minutes later.
Richard Foster pulled a goal back for the Dons courtesy of an error by Allan McGregor before Rory Fallon saw red for elbowing Dorin Goian in the closing stages.
Celtic dropped 12 points behind leaders Rangers a lacklustre goalless draw at home to Hibernian.
Gary Hooper and James Forrest both hit the woodwork for the home side, but it was another frustrating afternoon for the Bhoys to increase the pressure on Neil Lennon.
Motherwell remain Rangers' closest challengers after a thrilling 3-2 win at basement boys Inverness.
Inverness dominated for much of the game and broke the deadlock after three minutes when David Davis curled home before Shaun Hutchinson levelled six minutes before the break.
Andrew Shinnie put Inverness back in front after 76 minutes but Keith Lasley lashed home an equaliser 60 seconds later.
Tom Hateley grabbed the winner four minutes from time when his deflected free-kick found the net after Caley Thistle defender Chris Hogg was shown a straight red card.
The win gives Motherwell a three-point cushion over Celtic in second place and kept Caley Thistle at the foot of the table.
Dundee United eased the pressure on under-fire manager Peter Houston with a 4-1 win over Dunfermline at East End Park.
First-half goals from Paul Dixon and Lauri Dalla Valle gave United a comfortable advantage but Andy Kirk netted early in the second half to pull the home side back into it.
However, late goals from Johnny Russell and Gary Mackay-Steven secured a much-needed victory for the visitors.
Dean Shiels' second half penalty earned Kilmarnock a controversial 1-0 win over Hearts at Tynecastle.
Ian Black was sent off after 16 minutes for the hosts and Kilmarnock grabbed the winner on 55 minutes when Shiels scored from the spot after Marius Zaliukas felled Paul Heffernan
To compound Hearts' misery manager Paulo Sergio was sent to the stands for remonstrating with referee Alan Muir 13 minutes from time.
Kenny McLean netted his first goal for St Mirren as they scraped a narrow victory over St Johnstone at McDiarmid Park.
McLean grabbed the only goal of the game nine minutes from time to inflict defeat on managerless St Johnstone.