Celtic could win double - but is change inevitable?

Over his two spells in charge this season, 74-year-old O'Neill has averaged more Premiership points per game than any of his peers.

He has been more successful than Celtic could have hoped for when they brought him out of retirement after Brendan Rodgers' acrimonious departure, and again following Wilfried Nancy's ill-fated eight-game spell.

There is at least an arguable case that had he been in charge since Rodgers left, Celtic would be strong favourites to win the league by now.

On that basis, has O'Neill done enough to return as manager next season? Is his future contingent on winning the Premiership? Should Celtic look to the future? Does O'Neill want to keep managing in such a harsh environment at 74?

Right now these are unanswered questions, at least outside the walls of Celtic Park.

"I feel a sense of renaissance, coming back and working with young people, it's really, really terrific," O'Neill told talkSPORT on Tuesday when asked about the future.

"We'll have to see see how we stand at the end of the season, and that's nearly upon us now. "

While grateful to O'Neill, who was already a legendary figure, some Celtic supporters feel a fresh face in the dugout is needed.

Paul John Dykes, from A Celtic State of Mind podcast, believes O'Neill "should go and chill out and just enjoy retirement" at the end of the season.

"Martin O'Neill has been dreadfully let down by the Celtic board," Dykes told the BBC's Scottish Football Podcast.

"There's no way he came to Celtic in January, one week into a January transfer window, on the promise of four loanees and an out-of-contract player to win the double. No chance.

"So regardless of what happens, Martin O'Neill's legacy is intact."