Three points off top, so why is Sutton ruling Celtic out?

The counter-argument is it is difficult to see any of the top three winning all five of their post-split fixtures, such has been the unpredictable nature of this remarkable season.

The imperfections of all three teams have produced one of the most captivating Scottish title races in history. All three have now won on the same weekend on only two occasions this term.

Hearts continue to lead the way, showing real grit and character to fight back against Motherwell at Tynecastle on Saturday, as Rangers did a day later when they came from two goals down at Falkirk.

Celtic, however, have the most experienced manager in these title races, and a significant portion of their squad has also been there and done it before.

Sutton is right to highlight goal difference is slipping away from them, though. Hearts' is superior by six, while Rangers' is better by a sizeable 11.

Of course, that could prove immaterial if O'Neill's side manage to overhaul the points deficits on the league leaders and their city rivals, but it is certainly not making their task any easier.

Having failed to win 12 of their 33 Premiership matches this term, Sutton feels Celtic have also lost their fear factor. That may be evidenced by the way some opposition teams now approach games at Celtic Park.

St Mirren had 53% of the ball in the second half on Saturday, while Motherwell enjoyed almost 60% possession in the first period of their recent visit to Parkhead.

Sutton believes this stems from a lack of energy in midfield. Celtic went on to win both matches, but the concern is how such displays might translate against the top two, who both visit Parkhead after the split.

And, despite the home advantage, the former striker is not confident his old club can pick up the points they need in those crucial fixtures to climb the table.

"Celtic haven't beaten Rangers or Hearts in the league this season," Sutton said. "I watch them play every week. They are a hard watch.

"If they win the league it will be without a centre-forward. Everyone will drop points, but the fact Celtic are three behind Hearts means they don't have any room for error.

"I don't think Celtic's midfield has the thrust, dynamism or legs. That, allied with the centre-forward position, means I just think Martin O'Neill has too much to do - and the others are in a better place."