Champions Celtic lost ground on leaders and arch-rivals Rangers with a 1-1 draw away to Kilmarnock at Rugby Park today.
Belgian defender Joos Valgaeren rescued a point for Celtic after Martin O'Neill's men had fallen behind to Andy McLaren's first-half header.
Celtic are now four points behind Rangers.
The visitors were rocked in the 19th minute when McLaren's glancing header from nine yards gave keeper Robert Douglas no chance as it flew into the top corner.
After the break Celtic twice hit the post in a matter of seconds. Henrik Larsson struck the upright while Chris Sutton's follow-up from the rebound also hit the woodwork.
But Celtic eventually levelled when Valgaeren's 66th minute header beat Gordon Marshall from close range.
Both sides then had chances to win the game. Celtic were denied a late penalty when Hartson was brought down in the area.