Joe Ledley netted twice as Celtic ran out comfortable winners at home to Dundee in the Scottish Premier League.
The Welsh midfielder capitalised on a Rab Douglas fumble after Dundee had an early strike ruled offside.
Matt Lockwood was dismissed at the start of the second half for a foul on Gary Hooper, with James Forrest converting from the penalty spot.
Dylan McGeoch nodded in the third, then Ledley made it four with a close-range strike and Hooper fired in the fifth.
Dundee's new interim manager John Brown watched from the stand and may have been harbouring thoughts of a great escape from relegation after a promising first-half display.
But the league's bottom side were completely overwhelmed following Lockwood's dismissal.
And the margin of Celtic's victory could have been greater as they extended their advantage to 21 points at the top of the table.
With just six minutes played, Dundee had the ball in the net after Gary Harkins curled in a free-kick from wide on the left that evaded keeper Fraser Forster, but referee Kevin Clancy ruled Iain Davidson's flick-on offside.
Celtic recovered quickly from the early scare to take a 13th-minute lead when Emilio Izaguirre delivered a tempting ball that Douglas fumbled and Ledley shot had the easiest of finishes.
Dundee's Declan Gallagher could have done better with a header from a corner, then Brian Easton almost cashed in on a defensive blunder by Efe Ambrose, but the Nigeria defender recovered to clear.
Hooper warmed the hands of Douglas with a blistering 25-yard effort on 30 minutes as the hosts cranked up the pressure, then Izaguirre was kept out by the former Celtic keeper with another goal-bound drive.
With 10 minutes remaining of the first half, Forster was at full-stretch to tip over a lofted Harkins shot, then the former Killie man headed against the crossbar from a corner as Dundee endured a luckless spell.
Immediately following the restart, Anthony Stokes had the ball in the back of the Dundee net, but the referee ruled the Irishman had used too much force when barging an opponent aside.
Less than a minute later, Lockwood was dismissed for a tug on Hooper as the striker was sliding in to get on the end of a low Forrest cross.
Forrest stepped up to convert the spot-kick and hand Celtic a two-goal cushion.
The hosts extended their lead in the 58th minute when Stokes flighted a great ball towards the back post and McGeoch steered a strong header past Douglas.
Stokes then linked up with Hooper inside the Dundee penalty area but Douglas managed to keep out the close-range effort.
Dundee suffered a further blow when Ledley crashed in the fourth of the day after Stokes powered into the penalty area and cut back for the skipper to thunder home.
The visitors' misery continued into the closing stages of the match when Ledley clipped a ball for Hooper to control on his chest and shoot past Douglas.