Graeme Murty's first match as a permanent Rangers boss ended in a 2-1 Ladbrokes Premiership defeat at Kilmarnock, while Celtic extended their lead to eight points with a 3-0 home win over Aberdeen.
Having been handed the reins until the end of the season, Murty was hoping to boost his chances of a longer stay in the Ibrox hotseat by avoiding the kind of slip-ups his side suffered against Hamilton, Dundee and St Johnstone during his nine-game caretaker stint.
And it was looking positive as Declan John swept them ahead six minutes before half-time in the lunchtime kick-off, but former Rangers hitman Kris Boyd grabbed a quickfire brace late on to make it three home wins in a row for Steve Clarke's side.
The day got worse for Rangers when Celtic stretched their advantage at the summit with an emphatic home triumph over the second-placed Dons.
Right-back Mikael Lustig's deflected shot in the 40th minute was the highlight of a surprisingly tepid first half.
The Hoops stepped up the pace after the break and in the 68th minute former Aberdeen winger Jonny Hayes notched his first Celtic goal since joining in the summer, with French midfielder Oliver Ntcham wrapping up the points with a third.
Partick Thistle moved off the bottom as Niall Keown's first-half volley secured a 1-0 triumph over Hamilton.
Thistle went into the game two points adrift but Saturday's win - courtesy of Keown's second goal of the season - saw them climb to 11th place after Ross County's defeat at Hibernian.
Teenager Oli Shaw was the hero as Hibs came from behind to win 2-1 and ensure the Staggies will spend Christmas Day propping up the rest.
The 19-year-old bagged his third senior goal for the club to finally break the resistance of stubborn County and send Neil Lennon's charges head into Wednesday's Edinburgh derby with a five-point advantage over Hearts.
The table makes altogether more bleak reading for the relegation-threatened visitors, who saw Craig Curran's opener wiped out by Anthony Stokes' 100th top-flight goal in Scottish football as they plummeted to 12th spot.
Hearts' long wait for a victory at St Johnstone goes on after their three-game winning sequence ended with a 0-0 draw in Perth.
The Edinburgh club have not won in the Fair City since 2010, when Jim Jefferies was in charge.
Craig Levein's side had to play out the closing 15 minutes with 10 men after losing 16-year-old midfield prodigy Harry Cochrane to a red card shown by referee Kevin Clancy for a late lunge on Blair Alston.
Motherwell held on for a 1-1 home draw with Dundee after injuries to Chris Cadden and Elliott Frear saw them finish the game with 10 men.
Dundee had a strong wind at their backs in the first half at Fir Park but took the lead within two minutes of the restart when Paul McGowan finished brilliantly from 20 yards.
Craig Tanner levelled from the spot in the 61st minute. Frear's exit handed Dundee the advantage for the final 14 minutes, during which Josh Meekings was denied by a post and a brilliant save from Trevor Carson.