Here are five things we learned from the weekend's Ladbrokes Premiership action.

1. CELTIC ARE MISSING LEIGH GRIFFITHS

The Hoops' top scorer was absent for the fourth match running as a calf injury again ruled him out of the 2-2 draw with Hearts at Tynecastle. His replacement Nadir Ciftci has failed to build on the double he scored against St Johnstone two weeks ago and again looked off the pace against the Jambos, leaving it to midfielders Nir Bitton and Tom Rogic to find the net in Gorgie. Under-pressure boss Ronny Deila could do with having top marksman Griffiths back asap.

2. ABERDEEN NEED TO FIND A BETTER WAY TO HANDLE PRESSURE

After fighting their way back into title contention with a six-game unbeaten run, the Dons could have taken over at the top for 24 hours at least had they beaten Inverness on Saturday. But they blinked in the face of that opening and were forced to fight back from two goals down against the Highlanders to salvage a point, allowing Celtic to move clear at the top again with their draw in Edinburgh. It is the second time this season Caley Thistle have disrupted the Reds' ambitions and only raises questions about the mental strength of Derek McInnes' side.

3. WILLIE COLLUM IS MAKING CONTROVERSIAL CALLS A HABIT

The referee - the only Scot heading to Euro 2016 - found himself at the centre of more debate after his handling of Aberdeen's Pittodrie draw with Inverness. Just a week after getting two penalty decisions wrong during Rangers' defeat at Falkirk, the official was criticised by an angry McInnes for awarding another two suspect spot-kicks. It is the type of situation he will have to try to avoid if he is to make the latter stages of next summer's European Championships in France.

4. THE RELEGATION PLAY-OFF BATTLE IS NOT SETTLED YET

A run of seven games without a win put 11th-placed Kilmarnock in danger of losing touch with the rest of their rivals for the end-of-season demotion duel. But a 1-0 win away at Hamilton has closed the gap on Motherwell to a single point and the heat is now back on the Fir Park side, idle after their clash at basement dwellers Dundee United was rained off. Killie's winner, scored by Tope Obadeyi, had a large slice of fortune about it after it bounced wildly up off New Douglas Park's pitch, wrong-footing Accies keeper Michael McGovern, but it might just be the stroke of luck Gary Locke's side need.

5. LIAM BOYCE IS A CONTENDER FOR THE END-OF-SEASON PRIZES

Boyce has been Ross County's brightest spark this term and again underlined his importance to the Staggies with a hat-trick in their 5-2 win over Dundee. That haul took the striker's tally to 17 goals so far and with a place in Northern Ireland's Euro 2016 squad to be fought for, he is unlikely to let up just yet. But if he continues finding the net with such regularity, he has a decent chance of packing a player-of-the-year award or two in his suitcase for France.