When Heart of Midlothian beat Celtic 3-1 on 26 October to go eight points clear of the reigning champions at the top of the Scottish Premiership, most pundits had already decided it was now a two-horse race for the title.

Hibernian were only three further back in third, 11 behind their city rivals, but the thinking was that, even so early in the season, only Brendan Rodgers' side were capable of bridging such a gap. Indeed, there were few who were willing to stick their neck out and suggest even Hearts had a realistic chance of sustaining their challenge for a full season given Celtic's dominance in recent seasons.

Two months on and Derek McInnes' side are still there, albeit six points clear having played a game more than Celtic, who have since effectively shed two managers and are in turmoil under a third. Having also dismissed one head coach of their own, Rangers are, meanwhile, within three points of Celtic and will consider themselves also back in the race.

So how realistic is the challenge facing Celtic? Hearts are in their best position to challenge for the title for 20 years. Indeed, current head coach McInnes has surpassed the eight wins from 10 top-flight games that took the Edinburgh side to the top of the table before controversial owner Vladimir Romanov shocked Scottish football by sacking manager George Burley and their title challenge crumbled thereafter.

McInnes has been here before himself, his Aberdeen side having finished runners-up to Celtic four years in succession from 2015-2018. He has carefully avoided talking publicly about the possibility of a title challenge and believes there is "no pressure" on his team - certainly less than last season, when the side he would inherit finished in the bottom six.

"I would feel more mental fatigue if we weren't at the top of the league," he said. "I don't know how the players come across, but certainly when I'm in and around it, I think we're just enjoying it. And I know Lawrence Shankland and others I've spoken about, they felt more pressure last season.

"Because there's nothing worse than feeling you're underachieving. There's nothing worse than feeling that we should be doing better. All the criticism and finger-pointing that comes with that.

"So, at the moment, I actually don't think there is a pressure on anybody at the club. We're all just enjoying what we're doing." Enjoy a win over third-top Rangers on Sunday and McInnes may not be able to avoid publicly accepting his side are mounting a title challenge much longer.

New Celtic manager Wilfried Nancy hasn't been probed much about his title hopes. Not really so much an oversight. More a realization that the former Columbus Crew head coach's priority is to actually win a game since taking over from interim manager Martin O'Neill.

Four defeats in a row - having been the first Celtic manager to lose his first two in charge - and a large section of the Glasgow club's fans are already calling for his dismissal. Rodgers resigned the day after that October defeat at Tynecastle, but veteran former Celtic manager O'Neill steadied the ship with only one defeat - in the Europa League - in his eight games in charge.

Whether or not the Celtic hierarchy have regretted not keeping O'Neill in charge longer, they appear to be digging in, chief executive Michael Nicholson saying before Wednesday's loss at Dundee United that the board was "absolutely solid" behind the Frenchman while reports that they considered sacking him afterwards were dismissed.

O'Neill has hinted that Nancy did not spend much time mining his inside knowledge as the managerial baton was passed and the Frenchman seems determined to plough his own furrow, despite much criticism of his decision to ditch the four-man defence of his predecessors in favour of his own favoured three.

Indeed, he has insisted he will continue experimenting with his Celtic players and approach in a bid to find a winning formula. Asked if he would make adjustments, Nancy replied: "I get the question, but if you watch all the games that we play, all the time I adjusted something.

"The idea is not to stay still - we add improvements all the time. I have to change certain things to see players, but also see how I can adjust a few players, how I can mix players together." Nancy acknowledged the criticism has been "difficult to accept personally" but realises "we are judged on results".

Having presided over Celtic's longest losing streak since 1978, adding a fifth consecutive defeat for the first time since the 1952-53 season would mount further pressure on the Frenchman. When Danny Rohl took over from the sacked Russell Martin in October, Rangers were the ones in turmoil, eighth in the league with one win in seven.

Six wins and two draws in their eight league games since and they are nine points behind Hearts with a game in hand as the sides go head-to-head at Tynecastle on Sunday. Rohl was not shy in admitting the importance of the game - and acknowledging that his side are still struggling for form.

"But I'm very positive at the minute how we go, what we can improve," the former Sheffield Wednesday boss said. "We have still parts where we are not in the best, but even at the moment we take points. I think this is a good fundamental.

"I think then, with a win on Sunday, we will be just six points behind them, one more game in hand. If you take this then it could be three and then the situation will change from when I arrived to now.

"But we know there's still a long way to go, still a lot of games to play." Rohl says he can feel "confidence" growing in a side racked with self-doubt for much of the season and "the next six games are crucial" and only then "we'll know exactly where we are".

Much could swing on the January transfer market. Celtic have traditionally pulled away in recent seasons after January and McInnes quite rightly says "we've got to assume that other teams are going to improve".

This time, Hearts' challenge will be bolstered by the summer investment from Brighton owner Tony Bloom and Kazakhstan winger Islam Chesnokov is already poised to arrive from Tobol next month.

Rohl joked that he would like to sign "lots of players" on 1 January and is bound to be backed by the club's American owners in his first transfer window in charge. So too, if he survives that long, will Nancy, with his chief executive saying planning is already under way for the January and summer windows.

Okay, they have only won the Scottish title once - and that was in 1932 - but Motherwell fans have started to dream amid all the plaudits being received for their style of play under new manager Jens Berthel Askou. As BBC Scotland pundit Rory Loy said on the Scottish Football Podcast: "It's so easy to forget how well they're doing because you're not used to speaking about them in that fashion."

The Dane's side are just two points behind Rangers in fourth, albeit having played a game more, and Loy also pointed out that Aberdeen "have done remarkably well" to pull level with fifth-top Hibernian after seven league games unbeaten as they head to Celtic Park on Sunday.

Depending on how results go at Tynecastle, Celtic Park and at Tannadice, where Hibs visit on Saturday, "all of a sudden we could have the most exciting league in a number of years, decades".