Martin O'Neill warns defeat to Hearts would mean 'long way back' for Celtic

Defeat in Edinburgh would leave O'Neill's side facing a nine-point deficit in their quest to retain their title.

STILL GOT IT: Celtic manager Martin O'Neill with Stephen McManus and Shaun Maloney during at training session at Celtic Park. Pic: Andrew Milligan/PA Wire.

Martin O'Neill admitted Celtic cannot afford to lose Sunday's top-of-the-table showdown with Hearts at Tynecastle.

The Jambos are currently six points clear of both the Hoops and Rangers in the race to win the William Hill Premiership.