Are Celtic now favourites to win Scottish Premiership?
"There's a lot of work still to be done," he told BBC Scotland's Sportsound. "The Motherwell game is massive but if Celtic keep that intensity up, you can see them capitalising against a team who will want to play from the back. "I anticipate both teams will win on Wednesday and it will be hell for leather at Celtic Park.
" If it comes down to a showdown on the final day, former Scotland winger Pat Nevin sees three big factors that could favour Celtic. O'Neill has - in part, at least - healed the disconnect between fans and board that appeared before he returned for his second spell as interim manager this season. "Getting rid of the toxicity at Celtic Park has been immense," Nevin said.
"Celtic Park is an incredibly hard place to play when there is that noise and he's got it back. " Nevin also believes that "in his heart of hearts", head coach Derek McInnes "must be getting worried about the amount of injuries". Centre-back Craig Halkett and midfielder Marc Leonard both picked up serious injuries at Fir Park, while Nevin believes forward Claudio Braga has "looked exhausted" in the last two games.
Nevin also expects the spectre of 1986 - when two Albert Kidd goals for Dundee denied Hearts the title and handed it to Celtic - will be prominent in the build-up to a potentially nerve-shredding final day. Celtic captain Callum McGregor pointed out "it's in our hands" after Sunday's "huge win" over their city rivals. Only defeat by Motherwell on Wednesday, combined with a Hearts win, will prevent a final-day showdown.
Nevertheless O'Neill believes Celtic still have "two mountains to climb" if he is to lead them to the Scottish title for a fourth time - and his first in 22 years. "I've never been confident," the 74-year-old Northern Irishman said. "People have said to me about momentum and momentum can get shifted at any given moment.