Celtic manager Brendan Rodgers will seek answers to familiar failings after his side lost top spot in the cinch Premiership.

A 1-1 draw with Kilmarnock on Saturday allowed Rangers to move to the summit for the first time in two years when they beat St Johnstone 3-0 in Perth on Sunday. Celtic have now dropped 16 points – the same amount they shipped in the whole of last season, and half of those came in the final four games after they had already clinched the title. The champions failed to build on Kyogo Furuhashi’s first-half header and grew increasingly anxious in possession before David Watson headed home in stoppage time to earn Killie their fourth point against Celtic this term.

Rodgers had defended his side’s form in the build-up to the game but he admitted the below-par performance was not entirely unexpected. “We’ve had enough mishaps throughout the season so I’m not surprised, if I’m honest,” he said. “It was the same at Kilmarnock when we were ahead in the game, got pegged back and ended up losing. There’s been others where we haven’t been able to produce a level of performance. So I can’t say I’m surprised – that’s my honest answer.”

Celtic's Callum McGregor talks to Matt O'Riley and Paulo Bernardo during the draw against Kilmarnock.

The problem for Rodgers is there are few obvious answers to their issues. Key defender Cameron Carter-Vickers is due to return for next Sunday’s trip to Motherwell but the centre-back has been troubled by a hamstring issue on a regular basis this season. Right-back Alistair Johnston could be out for several more weeks, although his deputy, Anthony Ralston, set up Celtic’s goal. Left-back Greg Taylor only lasted an hour on Saturday before his calf tightened up. His departure affected Celtic’s fluidity and his replacement, Alexandro Bernabei, failed to deal with the cross that led to the equaliser.

In midfield, Reo Hatate has had four leg muscle injuries in the last year and is out for several more weeks, while the transfer of David Turnbull has left Celtic short of attacking alternatives in the centre of the park. Rodgers utilised four wingers on Saturday but none of them made a telling contribution and Liel Abada looks unlikely to feature in the near future, if ever again. Furuhashi found space to head home on Saturday but has missed the service he enjoyed from out wide last season, mainly through Abada and Jota, and was deployed in a deeper role behind Adam Idah on Saturday.

Captain Callum McGregor knows Celtic have to find answers quickly. “We’ve been in this position too many times this year,” he said. “We have a good run of games and then everything looks good. Then, all of a sudden, you turn up and something happens out of the blue where you think, ‘Where did that come from?’ That’s telling me there’s something missing. I’ll find the answer to that, I’m sure of it. I will leave nothing unturned until I find the answer to that question. One result can change everything and change the mentality. We have 12 games to turn that. I’ve got no doubt that if we do turn it, we can still go on and have a successful season.”

Kilmarnock have now taken seven points against the top two this term and their latest draw consolidated their place in fourth spot. But manager Derek McInnes stressed they had achieved nothing yet as they prepare to host Aberdeen and Rangers before the end of February. “We are the fourth best team in the league at the minute, but the league doesn’t stop now,” he said. “I am aware that there are so many teams who could still come past us and we have got to be aware of that. It is the team who finds form now that is important. We have got ourselves in a decent position but we have wins to get before the split and no-one will give us it.”

Celtic manager's 'not surprised' admission says it all - and options are limited as Rangers take top spot