Bombardment fails to materialise after two-minute warning sounded

A scruffy, patchy performance on a bumpy pitch was good enough to see off Inverness Caledonian Thistle, but only just. As they had against St Johnstone on Boxing Day, Celtic scored early, then protected their lead without playing especially impressively.

Again, they were unable to impose themselves and dominate despite an early goal. Commons showed flashes of class and quality which elevated him above the general ordinariness of the others, although Virgil van Dijk was again quietly impressive. The goal was Commons' 15th of the season, the attacking midfielder eclipsing Celtic's handful of strikers when it comes to finding the net. What a return he has delivered for the modest £330,000 paid to take him north from Derby County almost three years ago. Celtic were grateful for him because none of their other attacking players - Georgios Samaras, Anthony Stokes and especially James Forrest - made enough of an impression.

Inverness had plenty of the ball and a number of decent but not outstanding chances. That none of them was converted was down to a defence which has now recorded six consecutive clean sheets in domestic games. "The defence just always wants to keep getting better and to keep getting as many clean sheets as we can," said Efe Ambrose. "But we don't count them. In football, you just have to go out and do your best every time and, like today, when you only score one goal, keeping a clean sheet gets you three points. As defenders we know that if we can keep a clean sheet it is the most important thing because we always feel we can score a goal. We just try to ensure we don't concede goals. After the game against Barcelona [a 6-1 loss at Camp Nou earlier this month] it has been in our head that we just want to do better in every game."

It had looked as if it would be so much easier. When Graeme Shinnie gave away the ball in the fifth minute Celtic were ruthless. Emilio Izaguirre fed the ball to Commons, who played a one-two with Samaras to find a pocket of space in the penalty area before drilling the ball low through Dean Brill into the net. For an Inverness team that had recorded six clean sheets in its previous seven games it was atypically soft defending.

John Hughes's fifth game in charge of Inverness brought further evidence that he has been true to his word about intending to maintain the standards and style of his predecessor, Terry Butcher. Inverness were characteristically organised, fit and powerful. They got a foothold in the game within minutes of losing the goal, beginning to harass Celtic and force them on to the back foot. What they lacked was any real penetration or menace. Billy McKay got a sniff of goal only once, when a Nick Ross cross went over Ambrose. McKay did not seem to anticipate that it would reach him and only nodded a tame header into Fraser Forster's hands.

The Celtic goalkeeper had a quietly effective day. There was no call on him to produce anything spectacular but he made a handful of important saves which were a testament to his technique and concentration. The most eyecatching of them was the parry which pushed away Shinnie's vicious, curling shot just before half-time. There were routine stops to deny Aaron Doran, twice, and Shinnie again. Their best chance of all came at the death when Ross Draper should have buried Doran's cross, but he headed across goal without even forcing a save.

Stokes pulled a shot across goal in the first half, Commons glanced an effort narrowly wide, and Scott Brown lashed a shot at Brill after good work from Stokes. But Inverness never really looked like conceding a second. In the first half there was an amusing moment when Draper shoved over referee Crawford Allan because he had got in the way when he wanted to shoot. "If anyone was being booked it would be him for going down too easily," joked Draper. Celtic took the points, but Inverness were no pushovers.