Jan 5 (Reuters) - Celtic sacked manager Wilfried Nancy 33 days into his tenure on Monday and brought back former boss Martin O'Neill until the end of the season following Saturday's 3-1 Old Firm derby defeat by fierce rivals Rangers.
The loss left champions Celtic second in the table, level on points with Rangers and six behind leaders Hearts after 20 games.
“We know we’re in a big fight. We’re going to try and win the league," O'Neill told the club website.
"It won’t be easy, although it never is, but we’re halfway through the season, we’ve got a big fight on our hands, so we have to be up to the challenge.”
O'Neill, 73, won seven of his eight games in his second spell in charge before handing over to Nancy. The Northern Irishman managed Celtic from 2000-2005, winning a domestic treble in his first season, and in 2003 he led them to the UEFA Cup final, which they lost to Jose Mourinho's Porto.
Frenchman Nancy, 48, was appointed last month but endured a torrid start, managing only two wins in eight matches across all competitions. Under his watch, Celtic failed to keep a single clean sheet.
"By bringing Martin back to the club, we look forward with confidence, giving the team real focus for the challenges ahead," Celtic interim chairman Brian Wilson said.
"He is a manager the players, staff and supporters know well, with a peerless reputation in football and a deep commitment to Celtic."
Celtic have won the last four Scottish Premiership titles but fans have been unhappy with their lack of progress in Europe, staging protests throughout the season against what they see as the board's lack of investment in the transfer market.
The discontent boiled over on Saturday when Celtic were outplayed by Rangers.
Many fans headed for the exits early, while others directed their anger at Nancy and the club's board. Police were also stationed near the Celtic dugout as chants for Nancy's dismissal rang out.
This sacking marks yet another turbulent chapter in Celtic's season after Brendan Rodgers, who led Celtic to four league titles across two stints, quit as coach in October while in November shareholders halted an annual general meeting with boos, red cards and chants of "sack the board".
Peter Lawwell stepped down as club chairman last month, blaming increasing abuse and threats which had become 'intolerable'.
