Smart finishes from Georgios Samaras and Gary Hooper sent Celtic seven points clear at the top of the Scottish Premier League with a 2-0 victory at Dundee.
Samaras sent Celtic on their way to a fifth consecutive SPL victory with an overhead kick 16 minutes into a one-sided first half at Dens Park and former Scunthorpe striker Hooper lobbed Rab Douglas from 16 yards to seal the win in the 71st minute.
Inverness maintained their reputation as a tough side to defeat after twice coming from behind to hold on to second place with a 2-2 draw against St Mirren.
Inverness had lost only once in their previous 18 matches in all competitions and surpassed their goals tally for last season as they took their total to 44, two more than their entire haul in 2011-12.
Injuries and suspensions left St Mirren boss Danny Lennon a player short on the substitutes' bench but the Paisley side stunned Inverness when Dougie Imrie scored after just 76 seconds.
Andrew Shinnie equalised after 38 minutes only for Steven Thompson to put St Mirren back in the driving seat 10 minutes after the restart. However, Inverness captain Richie Foran headed the home side level again with 67 minutes played.
Motherwell produced a ruthless attacking display to defeat Aberdeen 4-1 at Fir Park and go level on points with Inverness in second place.
Tom Hateley headed home Jamie Murphy's cross after 10 minutes to give Stuart McCall's side the lead against the run of play. The hosts again punished Aberdeen's failure to take their chances as Murphy doubled their advantage on the half-hour mark, however Jonny Hayes powered through the midfield before powering an effort past Darren Randolph to reduce the deficit just minutes later.
Murphy notched his 10th goal of the season on the stroke of half-time to provide a timely boost for Well and Michael Higdon added a fourth 10 minutes into the second half.
Dundee United fought out an entertaining Tayside derby with St Johnstone as they drew 1-1 in their Boxing Day match at Tannadice.
Peter Houston's men looked like winning their first home SPL clash since August when defender Gavin Gunning headed them into the lead inside two minutes, but an own goal from team-mate Brian McLean put paid to that as Steve Lomas' Saints side fought back to ensure a deserved share of the spoils.
Ross County ended a nine-match winless run with a 1-0 victory over Hibernian at Easter Road. Richard Brittain headed in the winner after 57 minutes as the visitors won for the first time in almost two months to emulate Aberdeen and claim a second win over Hibs from two attempts this season.
Liam Kelly's first-half penalty was enough to give Kilmarnock a hard-fought 1-0 win against Hearts at Rugby Park after Gorgie defender Andy Webster had fouled James Dayton.