CELTIC are in danger of forgetting what it feels like to be unhappy.

As the tax men loom over their biggest rivals, the team at the top of the table have an increasingly clear view of a joyous climax to the season. It's early February, and Celtic have a recent record of falling on their face, but it requires a stretch of the imagination to see them being stopped. Tynecastle should offer almost as hard a test as any but they made a mess of Hearts, smashing them to bits on the way to a 16th consecutive domestic victory.

The Edinburgh side might argue that the game would have looked entirely different if the officials had spotted that Stephen Elliott's header had crossed the line in the second minute. That is a forgivable view for them to adopt but it is undermined by the sharpness and menace of Celtic's attacking for the rest of the evening. It was inconceivable that goals would not have arrived for Celtic even if they'd had to come from behind to get them. They were so dominant that what appeared an explosive early controversy became increasingly less relevant.

The match started with a customary peep of the referee's whistle, although it may as well have begun with a detonator being pressed. Andy Driver's corner found Andy Webster at the back post and his header returned it to Elliott in the goalmouth. The Irishman should have made certain but his header struck Joe Ledley on the goalline before being clawed away by Fraser Forster. Too late: the ball had crossed the line. Tynecastle erupted and the stadium announcer even began the music which accompanies a Hearts goal, yet none was given.

The moment was over in a flash and assistant referee Andy Tait's role was unenviable, especially as Charlie Mulgrew was on the post blocking his view. Referee Willie Collum could not make the call unaided. It was a repeat of the let-off Celtic enjoyed when a Lee Wallace header crossed the line in the Old Firm game in December but was neither spotted nor given by the officials.

The injustice was hard on Hearts. Their grievance was quickly compounded by Celtic sweeping upfield to take the lead. The home support was still in a ferment as their side scrambled back to repel a flowing move. James Forrest's ball across the box ricocheted off Georgios Samaras into Scott Brown's path. Hearts allowed him just enough room to bury a low shot deep in the far corner. Brown planted himself in front of the Gorgie Stand and flung his arms wide in celebration, as if the Hearts supporters there hadn't had enough to anger them in the previous 30 seconds.

Hearts were entitled to feel they did not do a lot wrong at that first goal and the same could be said of the second. Again it was scored by a midfielder when the ball broke to him in a box well-populated by defenders. Forrest's shot struck a Hearts player and fell to Victor Wanyama, who controlled and instantly turned to rifle a shot into the top corner. This accomplished young Kenyan has earned plaudits both in defence and midfield, and now and again he pops in a cracking goal. It was a striker's finish.

Celtic were rampant. At the third goal, after barely half an hour, Hearts were truly opened up and exposed for the first time. Brown dispossessed Marius Zaliukas and passed to Hooper, who fed the ball wide to Samaras. The chipped cross he delivered into the six- yard box was perfect for Joe Ledley to connect with a diving header. Hearts were all over the place.

Paulo Sergio, the Hearts manager, had changed his usual formation and gone with a back three of Ryan McGowan, Webster and Zaliukas, hoping an extra body in midfield might help to suffocate Celtic. The idea was sound enough but Celtic's midfield was too confident, mobile and sharp for it to succeed. Wanyama was an anchor, Brown revelled in it all and Forrest and Ledley offered danger and width. Samaras' runs caused havoc. It's not often that Hearts fail to get a toehold in a match at Tynecastle but at no point were they comfortable in this one. Shots by Scott Robinson and Suso Santana were as close as they came. Most of the night was spent in growing anxiety that the scoreline might really run away from them.

They thought they had a minor reprieve when Ledley's shot hit a post, but it wasn't to be: Celtic merely scored from the ensuing corner. Charlie Mulgrew crossed to the back post and Wanyama nodded it down before Hooper forced it into the net. That was enough for plenty in the home support to melt away. Those who remained jeered Brown when he was substituted after 76 minutes to allow Pawel Brozek to make his Celtic debut.

The visiting fans lapped it all up. Depressingly there was an early "ooh ah, up the 'RA" chant but most of their song book celebrated the ease of their win and their admiration of the work being done by Her Majesty's Revenue and Customs. The songs were the only taxing thing about their entire night.