Celtic held firm at the top of the Scottish Premier League with a 1-0 win over Inverness, while Rangers thumped Dunfermline 4-1.
Joe Ledley's 16th-minute goal was enough for Neil Lennon's side at Celtic Park, where there were two red cards shown on Saturday.
Wales midfielder Ledley tapped in a cross from James Forrest, restoring Celtic's four-point lead after Rangers had won earlier in the day.
Celtic were reduced to 10 men when Swedish defender Daniel Majstorovic was harshly red-carded on the hour-mark after a challenge on Jonny Hayes.
But the visitors had Steve Williams sent off 18 minutes later after he picked up his second yellow card.
Earlier, rivals Rangers came from behind to secure a 4-1 win at lowly Dunfermline.
Andy Kirk slid in to open the scoring for the hosts on 16 minutes, moments after they had hit the post and had a penalty appeal turned away.
But Ally McCoist's men were ahead before the break thanks to goals from David Healy and Lee McCulloch.
They sealed the win in the second half thanks to strikes from Sone Aluko and Salim Kerkar.
Elsewhere, Dundee United hammered St Johnstone 5-1 at McDiarmid Park.
Own goals from Steven Anderson and Callum Davidson handed Dundee a 2-0 lead, before the former pulled one back for his side.
But the visitors helped themselves to three goals in the last seven minutes, with Johnny Russell, Jon Daly and Milos Lacny netting.
Hearts secured a 1-1 draw at Kilmarnock after Suso Santana cancelled out Paul Heffernan's 79th-minute effort.
Third-placed Motherwell played out a 0-0 draw at St Mirren, while Aberdeen were held to a scoreless draw by Hibernian.