Former Celtic and Aston Villa midfielder Stiliyan Petrov believes his former boss Martin O'Neill "is doing miracles" by keeping the Scottish champions in a title race that the ex-Parkhead star believes they are still favourites to win.
Celtic are third in the Premiership, six points behind leaders Hearts and two behind rivals Rangers, with a game in hand on both.
Petrov was an integral part of O'Neill's side that reached the Uefa Cup final in 2003 and feels that if anyone can get Celtic over the line to defend their crown, it's the 73-year-old Northern Irishman, twice summoned back to the club on an interim basis this season.
"He is doing miracles," Petrov said. "I think the club has been going through a really difficult time in the last couple of months.
"The fans, the board, the changing of managers; it's been really challenging I think for the players as well. So all of a sudden he's walking into the club for the second time, he tried to get things right.
"I'm not sure about the new signings. The recruitment hasn't been right for him. So I think he's finding it really challenging.
"I look at his interviews - he's at that age where he needs calmness and relaxation rather than nerves and stress but it seems like he's taken it on and he wants to do the right thing. The right thing is to win the league."
Regardless of the outcome of an ever-fascinating title race, Petrov feels change is needed at Parkhead with sections of the fanbase at loggerheads with the club's hierarchy.
He is unsurprised by the discontent running through the club's support and called for a "restructure".
"I think Celtic as a club have to restructure and I think the fans have seen that. I think the last two transfer windows have shown that as well.
"You have to have a different vision. You have to make a plan and take action.
"The fans are right to [protest] because they've seen a lot of success.
"They want the club to go in the right direction. They are not happy - the board haven't made the right decisions to bring in the right players and give the managers the tools that they need.
"But they're still in a title race which is good to see even through the difficult moments they've been through."