A controversial night at Tynecastle saw Celtic lose 2-0 to Hearts, with Joe Ledley and manager Neil Lennon both seeing red for the visitors.
Ian Black and David Templeton were the heroes for the Edinburgh side on the night, with Celtic showing none of the class and the style that they displayed in their 9-0 dismantling of Aberdeen.
It was an absorbing first half and Stephen Elliott was unlucky not to put Hearts 1-0 up after 13 minutes, the Irishman hitting the bar with his header.
Elliott headed wide again on 26 minutes, but two minutes later his team had the lead.
Midfielder Black took a short Rudi Skacel free-kick and let fly from 30 yards, with Bhoys defender Daniel Majstorovic deflecting the ball into his own net.
Gary Hooper had Celtic's best chance towards the end of the half, but saw his shot blocked by the feet of Kello.
The game boiled over ten minutes into the second half when Ledley saw red for a bad tackle on Black, and two minutes later it was 2-0.
Skacel raced down the left and crossed for the unmarked Templeton to slide past Frazer Forster from 12 yards.
Celtic were denied a clear penalty when Hearts' Ryan Stevenson appeared to handle in the box, leading to a sending off for the protesting Lennon in the Celtic dug-out.