THE next time a letter is mentioned in connection with Celtic it will be a capital C beside their name to denote they are the new SPFL Premiership champions.

Three days on from the furore of their William Hill Scottish Cup semi-final defeat to Inverness Caledonian Thistle - when the non-award of a penalty prompted the club to dig out their stationery set to pen a missive to the Scottish Football Association looking for an explanation - Ronny Deila and his players comfortably demonstrated that being denied the prospect of a treble would not halt their determination to conclude the campaign with a double. With the League Cup already in the cabinet, this victory stretched their advantage at the summit to eight points over Aberdeen with just five games of the season remaining. They will surely be champions soon enough, even if a late Dundee consolation goal did give them a few anxious injury-time moments. They return to the city on Sunday to face United for the seventh time this season, the title surely now only weeks away.

The fall-out from the Josh Meekings Hampden handball that wasn't meant every incident here was placed under far greater scrutiny than would normally have been the case. Even the slightest perceived injustice was jeered with all the venom of a gaggle of schoolchildren booing a pantomime villain who has suddenly appeared from behind a beanstalk. Given this climate of suspicion it was almost inevitable that referee Calum Murray or one of his officials would do something to irritate one side or the other and on this occasion it was Dundee who trotted off the field harbouring the greater sense of grievance.

The manner of Celtic's opening goal after 32 minutes was the main source of their complaint. Murray had chosen to wave play on after a foul by Thomas Konrad, the Dundee defender, on Gary Mackay-Steven only to then call back play once Celtic had conceded possession. From that point, however, the failings were all on the part of the Dundee defence. Stuart Armstrong hoisted the free kick high into the box, Virgil van Dijk knocked it back and Mackay-Steven was able to take a touch before rocketing a shot high into the net. That it was a former United player that had done the damage added further salt into Dundee wounds.

Given Dundee also felt they should have had a penalty when Jason Denayer barged into Greg Stewart - it would have been very soft - then it was perhaps not a surprise that the match officials' march off the field at half-time was to the soundtrack of an irate Paul Hartley chirruping angrily in their ears.

Those, relatively tame, controversies aside, Celtic were well worthy of their victory even if their performance was a touch laborious at times, their play lacking its usually fluidity. That Craig Gordon, in the Celtic goal, did not have a save of note until Dundee scored their late consolation, however, told the story of a game played largely in the opposition half with Mackay-Steven, Armstrong and James Forrest all buzzing around eagerly, and Leigh Griffiths a willing runner in the lone striker's role.

Celtic created a few half-chances before finally moving in front. Mackay-Steven lifted a chance over the crossbar, van Dijk headed a corner straight into Scott Bain's arms, and Griffiths fizzed an effort into the side netting as Celtic enjoyed almost total territorial domination, Dundee restricted to occasional flurries on the counter that came to nothing.

The second half brought more of the same as Griffiths drew a fine save from Bain. Celtic needed a second goal, though, to confirm their superiority and it duly arrived after 63 minutes. James McPake hauled down Armstrong about five yards outside the penalty area and van Dijk, just as he had done in the semi-final, cracked the free kick past Bain with pace and precision.

Dundee's response three minutes from time - Jim McAllister converting a Paul McGinn cutback low past Gordon - gave the home support some belated heart but ultimately came too late to be of significance. This was their first home league defeat of the year and extended their winless sequence against Celtic to 19 matches. With their place in the top six already assured, they retain an outside chance of qualifying for the Europa League should Inverness win the Scottish Cup but this wasn't a night where they looked likely to garner further points to bolster that mission. Celtic were clearly not of a mind to give them a hand.