Andy Waterworth's 14th league goal of the season and a penalty from Aaron Burns was enough to keep David Jeffrey's men ahead of the chasing pack.
In what proved a lively opening period a throw-in by Billy Joe Burns found Jamie Mulgrew who connected well but his 25 yard volley flew inches over.
Glentoran responded by forcing a fine save out of Jonathan Tuffey when Mark Miskimmon chested the ball down on the six yard box and got in his shot only to be denied by the Linfield stopper.
Tuffey was called into action again to push away a long range short from Mark Clarke in a lively start to the game.
The Blues took the lead early in the second half when former Glentoran striker Andy Waterworth poked the ball home after a scramble in the box by Jason Hill.
Any hopes the Glens had in getting back into the match all but ended when Linfield were awarded a penalty after Mark McAllister was upended and Aaron Burns blasted home to make it 2-0.
The Blues continued to boss the game and Waterworth was denied a second thanks to a brilliant save by Elliott Morris.
The Glens pulled a consolation goal back on 90 minutes through David Scullion and in added time Mark Clarke saw red and was sent off after a clash with Mulgrew.
The victory puts Linfield six points clear going into 2014.
Second placed Cliftonville had to settle for a draw after a dramatic finish at Seaview.
The Reds had been leading 1-0 thanks to a Liam Boyce penalty, but up popped Colin Coates to level matters three minutes into stoppage time.
No-one was more relieved at Seaview than Coates, he had missed a chance to fire the Crues ahead by missing his spot kick after Paul Heatley was brought down by Barry Johnston.
The drama continued with another penalty this time for the Reds after Murray was felled by Magowan. Liam Boyce swept home the spot kick to give the visitors the edge in this tightly contested game which finished 1-1.
At Mourneview Park Mark Patton ended 17 years of Boxing Day pain for Glenavon when he scored a dramatic last minute winner against Portadown as it ended 3-2.
The Glenavon winger drilled a low shot home from an acute angle to send the home fans into raptures and just a few seconds later the final whistle secured that historic win.
The first chance of the game fell to the home team on four minutes when Guy Bates, hat-trick hero in the previous game at Shamrock Par, curled a shot just over. A few minutes later Rhys Marshall shaved the bar with a header following a corner by Kyle Neill.
A mistake by goalkeeper Andy Coleman when he missed the ball almost let in Darren Murray but Lindsay and Marhsall did well to clear the danger.
Ports keeper David Miskelly made two fines saves to deny Bates, first when the Glenavon striker was set up by McGrory and then with the follow up effort from Bates.
Glenavon were beginning to get on top and it was no surprise they took the lead on 40 minutes. A lob by McGrory was met by Gary Hamilton and he fired a half volley past Miskelly.
It got even better for the Lurgan Blues when Rhys Marshall hooked in a corner from Kyle Neill.
Portadown made a great start to the second half and pulled a goal back on 49 minutes. Peter McMahon saw his initial shot saved but was quick to pounce on the rebound to hit the back of the net.
Five minutes later it was 2-2 with Darren Murray making amends for missing a great chance in the previous attack when he reacted first to a loose ball following a corner by Casement.
Gary Twigg must still be wondering how he failed to score when presented with a clear run on goal, he did everything right but fired wide of the goal on 63 minutes. Andy McGrory smashed a shot off the woodwork before Patton had the final say.
A late goal too at Ferney Park saw Ballinamallard and Dungannon finish 1-1.
Johnny Topley should have fired Dungannon ahead but somehow sliced his shot wide after being set up by Stefan Lavery.
At the other end Jason McCartney was guilty of failing to find the net, but the home side forged ahead on 24 minutes when Stuart Hutchinson stabbed the ball home following a scramble.
Dungannon kept plugging away and were finally rewarded on 88 minutes when Jamie Glackin hit the target.
Two goals from Ballymena skipper Allen Jenkins gave United the derby spoils 3-2 at Coleraine.
It was Coleraine who created most of the early chances with Stephen Carson denied by Stuart Addis who was injured making the save and he needed treatment for seven minutes before the game was restarted.
Gareth Tommons also went close before United's Gary Thompson also failed to make his effort count.
United hit the front on 42 minutes through Alan Teggart and deep in first half stoppage time Allen Jenkins doubled the advantage.
Gareth Tommons gave Coleraine a way back on 68 minutes but Ballymena restored their two goal cushion through skipper Jenkins.
There was still time for Coleraine to salvage something from the game when Owen Bradley pulled another goal back on 74 minutes but Glenn Ferguson's side held on for a deserved three points.
Warrenpoint's floodlight problems surfaced again with another failure which almost saw the game with Ards postponed.
The same floodlight, which recently forced the game with Glenavon to be postponed, went out again with the home team leading 1-0.
The lights did eventually come on at Milltown and the second half started late, but at least the game was able to finish on this occasion.
Warrenpoint had taken the lead in a first half of few chances. A speculative shot from Stephen McCabe seemed to be covered by Ards keeper Graeme McKibbon but he let the ball slip through his hands and into the net.
The home team were reduced to ten men on 59 minutes when Darren King picked up a second yellow card, but Warrenpoint increased their lead and it that man McCabe again with a neat finish to seal the points in a 2-0 victory.
Thursday's results in full:
Ballinamallard Utd 1-1 Dungannon Swifts
Ballinamallard Utd: Hutchinson 32.
Dungannon Swifts: Glackin 82.
Coleraine 2-3 Ballymena Utd
Coleraine: Tommons 68, E Bradley 74.
Ballymena Utd: Teggart 42, Jenkins 45+5, 70.
Crusaders 1-1 Cliftonville
Crusaders: Coates 90+2.
Cliftonville: Boyce 49 (PEN).
Glenavon 3-2 Portadown
Glenavon: Hamilton 40, Marshall 43, Patton 90+3.
Portadown: McMahon 49, Murray 56.
Glentoran 1-2 Linfield
Glentoran: Scullion 88.
Linfield: Waterworth 49, A Burns 60 (PEN).
Warrenpoint Town 2-0 Ards
Warrenpoint Town: McCabe 24, 62.