Whatever his failings at continental level, there is little prospect of Deila being unable to guide the Scottish champions safely to a fifth consecutive domestic title.
Victory over John Hughes’ side appeared in doubt when Miles Storey cancelled out Callum McGregor’s early opener but Celtic, while far from wholly convincing, secured maximum points through Leigh Griffiths’ 19th goal of the season and a late own goal from Danny Devine.
An early morning pitch inspection by referee Willie Collum gave the fixture the green light. The playing surface had held up reasonably well despite heavy overnight rain and snow, albeit with some areas having retained more moisture than others.
But the decision was taken with scant regard for those supporters who had to travel up the A9, at times through near white-out conditions, for the 12:15pm kick-off. As is increasingly the case in Scottish football, live television coverage took precedence over the paying punter.
Any inconvenience experienced by the Celtic fans would certainly have been eased by their team’s start to the match which saw McGregor provide the lead with his fine seventh-minute strike. Hughes would be entitled to ask questions of his defence who backed off the Celtic midfielder when he collected a pass from Stefan Johansen and strode purposefully towards the edge of the Inverness area.
McGregor didn’t need a second invitation, taking full advantage of the time and space afforded to him as he drilled a low left-foot shot beyond Owain Fon Williams’ left hand into the corner of the net.
The home side’s response was brisk and almost saw them back on level terms just two minutes later. Iain Vigurs’ corner from the right caught the Celtic defence flat-footed, leaving Gary Warren with a free header at goal. His powerful close-range effort was kept out by Craig Gordon’s chest, the ball eventually finding its way to Josh Meekings who curled a shot just wide.
Both teams contributed energetically to an entertaining start and Celtic should have doubled their advantage when skipper Mikael Lustig wastefully sent a header over from six yards after being picked out by McGregor’s corner.
Set pieces were proving a problem for both teams and Inverness were fortunate that more poor marking was not punished by Jozo Simunovic when the big Croatian defender’s header from a Stuart Armstrong corner drifted just wide of Williams’ right-hand post.
Much of the early impetus had disappeared from Celtic’s play, however, and Inverness were forcing them onto the back foot more regularly as half-time approached.
When it came, Inverness’ 39th-minute equaliser was fully merited on the balance of play. Armstrong lost possession cheaply in midfield, allowing Liam Polworth to pick out Storey’s run in between Celtic’s central defensive pairing of Dedryck Boyata and Simunovic.
The on-loan Swindon Town striker was able to easily outmuscle Boyata and when his first shot was parried by Gordon, he showed good composure to latch onto the rebound and tuck it home from around eight yards.
Nir Bitton sent a sweetly struck shot from 25 yards narrowly wide as Celtic tried to reclaim the ascendancy. But Inverness, their sense of belief replenished by Storey’s goal, came close to taking the lead four minutes into the second half when Warren headed just wide from James Vincent’s cross.
Celtic needed an injection of creativity and it came with the arrival of Scott Allan as a 54th-minute replacement for Armstrong. It took just five minutes for the former Hibs midfielder to make the impact desired by Deila as he contributed to Griffiths restoring the visitors’ advantage.
Allan showed vision and intelligence as he linked up with Kieran Tierney down the left, his pass sending the young left-back racing into the Inverness penalty area where his low cross was slammed home from close range by Griffiths.
Celtic immediately made their second change of the afternoon, Carlton Cole finally making his debut for the club as he replaced Tom Rogic. The former England striker almost announced himself in dramatic fashion as his first meaningful touch saw his close-range header from McGregor’s cross superbly saved by Williams.
Deila’s men had regained the lead and the initiative, but Inverness remained ambitious as Hughes sent on strikers Tobi Sho-Silva and Andrea Mutombo in a bid to forage a second equaliser. It almost came by way of an own goal, Johansen sparing Lustig from that fate when he cleared off the line in a melee following a corner.
Instead, it was an own goal at the other end which settled affairs firmly in Celtic’s favour five minutes from time. Griffiths’ stinging left-foot shot from 20 yards was parried by Williams, the ball breaking to Cole whose poor first touch appeared to have let the chance slip away. But in the ensuing scramble, which saw Inverness players claim for handball against Cole, it was Devine who diverted the ball over the line.