Ian Harkes and Dundee United were left humiliated as Celtic hit them hard and often to come away with a huge win, while James Sands, Malik Tillman, and Rangers were a little more merciful in their victory.
Dundee United 0-9 Celtic
Dundee United was no match for the defending Premiership champions as they clearly dominated the game from start to finish to leave Tannadice Park with all three points.
Cameron Carter-Vickers played his part in keeping the clean sheet as he completed 94 percent of his passes and won four duels. On the other side, it was a day to forget for Ian Harkes as he only completed 67 percent of his passes in 58 minutes of action.
The visitors started their assault on the Dundee United goal in the 15th minute when Kyogo Furuhashi finished off a cross from Jota to give them the lead.
They then hit three in the span of six minutes to put the game well out of reach. Furuhashi completed his hat-trick with strikes in the 40th and second minute of first-half stoppage time. Jota would then end it with a goal of his own.
The second half was more of the same as Celtic came out firing on all cylinders.
Liel Abada added a fifth for the team in the 50th minute. The Tangerines were slow to stop the passing from their opponents and Matthew O’Riley would pass the ball to the Israeli international to tap in.
Josip Juranovic made it 6-0 in the 55th minute with a strike after the initial free kick was blocked by the wall. Abada followed suit with two more goals in the 59th and 77th minutes respectively to complete his own hat-trick.
Carl Starfelt completed the rout in the 81st minute when he headed in a David Turnbull corner kick.
The win keeps Celtic atop of the standings on 15 points while Dundee United is rooted at the bottom with one point.
Rangers 4-0 Ross County
Rangers celebrated their return to the Champions League with a win over Ross County at Ibrox to keep them two points behind the leaders.
Both James Sands and Malik Tillman started for the Light Blues, with the former completing 86 percent of his passes and winning five duels, while the latter completed 83 percent of his passes and won six duels.
It took some time for the hosts to finally open the scoring in the 24th minute when John Lundstram put his team ahead with a long-range strike that took a deflection before going in. Antonio Colak doubled their lead 15 minutes later with an acrobatic finish.
The Croatian striker scored his second on the day in the 58th minute when he was left wide open in the 12-yard box to put away a pass from Ryan Kent. Steven Davis completed the scoring when he put in a back-heeled pass from James Tavernier.
Rangers remain in second place in the standings on 13 points.
Elsewhere in the Scottish Premiership, Joe Efford came on to play 32 minutes as Motherwell suffered a narrow 2-1 defeat to Kilmarnock.
Dante Polvara was on the bench while there was still no sight of Christian Ramirez as Aberdeen secured a 5-0 win over Livingston.
In the Championship, Brian Schwake recorded a shutout as Greenock Morton came away with a 1-0 win over Inverness CT.
Down in League One, Emmanuel Johnson was relegated to the bench for FC Edinburgh earned a 2-0 victory over Clyde.