Celtic beat St. Mirren 2-0 to record their first Scottish Premier League win since October and extend their advantage at the summit.
Victor Wanyama, who had already had a shot blocked on the line, gave Neil Lennon's team a 15th-minute lead when he tapped in the rebound from his own header. Celtic then had a succession of penalty claims turned down by referee Calum Murray as Gary Hooper and Beram Kayal took tumbles in the box.
Craig Samson made a superb save to stop a point-blank header from Scott Brown early in the second half, before Mikel Lustig cracked a header off the bar. Hooper made sure of the points in the 83rd minute, when he fired into the roof of the net from close range after the ball fell kindly for him following a Charlie Mulgrew corner.
The win extends Celtic's lead to four points over Motherwell, who leapfrogged Inverness Caledonian Thistle following a 3-2 win over Hibernian and have a game in hand.
Celtic, who hadn't won at home in the league since 7 October, started brightly and as early as the fifth minute Wanyama saw his header blocked on the line by Samson. After grabbing his first goal for Celtic in midweek, Adam Matthews looked in the mood to add more with his rising shot from the edge of the box going just over.
The Bhoys had a decent penalty claim in the 14th minute, when Hooper got sandwiched between Jim Goodwin and Paul Dummett as he attempted to get on the end of Kayal's lofted pass into the box but referee Murray ignored his pleas.
However, Celtic grabbed the opener a minute later through Wanyama. The Kenya international saw his initial header from Mulgrew's corner saved by Samson on the line, but the keeper spilled it back into his path and he tapped the rebound in.
Celtic had yet another penalty claim turned down after Kayal went down under Goodwin's challenge, but his protests were waved away.
St. Mirren had their first real chance just after the break, when Kenny McLean ran at the Celtic defence before making room for a shot, but he sliced his effort high and wide.
Only a superb save from Samson stopped Celtic doubling their advantage in the 51st minute. Samaras's cross was headed back across goal by Hooper where it was met by Brown, but his point-blank bullet header was superbly kept out on the line.
Swedish defender Lustig saw his header from a Mulgrew corner smash off the bar as the home side threatened again. Celtic were nearly made to rue their missed chances when the ball fell kindly to John McGinn in the 66th minute, but his strike went straight to Fraser Forster.
Mulgrew came within inches of making it 2-0 with a curling effort from a free-kick before Hooper got the second in the 83rd minute. The striker lifted the ball into the roof of the net from four yards after Mulgrew's in-swinging corner had ricocheted off Marc McAusland.
Tannadice thriller, Kilmarnock prevail
Elsewhere, Inverness fought from being 3-0 down after ten minutes to claim a 4-4 draw with Dundee United at Tannadice, St. Johnstone held Hearts to a 2-2 draw, Kilmarnock won 2-0 away to Aberdeen, and Ross County and Dundee ended 1-1.