The former Hearts player had previously only scored at Spartak Moscow and Dundee United since arriving from Tynecastle in January 2007.

But his 25-yard drive just before the break allowed the Celtic fans in the official crowd of 56,504 to enjoy the sight of the Scotland midfielder’s enthusiastic goal celebration.

When Fir Park striker David Clarkson was shown a straight red card in the 57th minute for a push in the face of Parkhead substitute Paul Caddis, on for Shaun Maloney, it was effectively all over for the visitors.

They stuck to their task but former Well favourite Scott McDonald fired in the clincher from the edge of the box in the 70th minute to cement the Parkhead side’s place at the top of the SPL and blow away any lingering disappointment from Wednesday’s draw against Manchester United in the Champions League.

After the excitement of midweek, there was understandably a more low-key start to this game which was watched by a noticeably smaller crowd.

Motherwell took a few minutes to realise they might get something from the game and almost took the lead with their first purposeful foray.

In the 10th minute Maloney had to clear John Sutton’s header off the line, just as he had done against Manchester United in the Champions League in midweek when Dimitar Berbatov’s shot was goalbound.

Television pictures suggested the ball had crossed the line but play continued and the other end a minute later, McDonald reached the bye-line and cut the ball back to midfielder Scott Brown who drove his shot from 14 yards off the outside of the post.

In the 21st minute McDonald turned 25 yards from goal and sent in a right-footed drive which Motherwell keeper Graeme Smith was glad to touch over the bar, the visitors emerging unscathed from the set-piece.

The Lanarkshire side grew in confidence and after a neat exchange at the edge of the Celtic box, Hoops’ defender Gary Caldwell prevented Clarkson bursting through on goal with a well-timed sliding tackle.

Just before the half-hour mark McDonald got his head on the end of a Hartley corner, forcing Smith in to another fine block down at his left-hand post.

Celtic turned the screw as the interval approached and in the 39th minute Cillian Sheridan fired in an angled drive from 18 yards which Smith forced past the post for another corner which Motherwell again survived.

The pressure intensified and McDonald had the ball in the net but referee Dougie McDonald blew for an infringement.

However, just seconds before the break Hartley picked up Marc Fitzpatrick’s clearance from a Sheridan cross and fired in a low drive from 25 yards to the cheers of the home fans.

Four minutes after the restart Maloney was replaced by Caddis, a substitution that suggested an other injury to Strachan’s beleaguered squad.

Celtic were not at their best but still looking too good for Motherwell and in the 53rd minute Sheridan climbed above Mark Reynolds once again to head just past the post.

But in the 56th minute Motherwell passed up a great chance to equalise when Porter somehow missed the target from close range after Sutton had chested Stephen Hughes’ cross in to his path.

Worse to follow for the visitors a minute later when Clarkson was shown a straight red after pushing Caddis in the face as they tussled for possession down the line.

Celtic appeared to be in control but the fans were unhappy when McDonald took the ball off Andreas Hinkel’s toe after the German had brushed his way in to the Motherwell box, the Australian’s shot spinning wide of the target.

Belief drained from the Lanarkshire side and in the 70th minute McDonald secured the points when he twisted and turned at the edge of the Motherwell box before dispatching a low drive past Smith and in to the far corner.

Celtic dominated the final stages, the hungry McDonald firing over the bar from close range following yet another corner while Caddis drove wide after another swift counter-attack had left the visitors wide open.

Motherwell were all over the place in the closing stages and the final whistle confirmed the champions had moved five points clear of rivals Rangers who play Kilmarnock at Rugby Park on Sunday.

end