Celtic manager Brendan Rodgers warned the rest of Scottish football that his side will continue to improve after they maintained their treble push with a 6-0 victory over Inverness.
A 14-minute hat-trick from Moussa Dembele helped Celtic into the quarter-finals of the William Hill Scottish Cup after a clinical performance against the only team to deny them victory in 30 domestic matches this season.
Mikael Lustig broke the deadlock in the 20th minute after an impressive piece of penalty-box skill and Dembele completed his second treble inside six days before the hour mark.
Kieran Tierney and skipper Scott Brown added late goals as the runaway Ladbrokes Premiership leaders gave the home fans in the 25,577 crowd value for money on a bitterly cold day in Glasgow, with wingers James Forrest and Scott Sinclair providing five assists between them.
Rodgers said of his players: "Their attitude was first class, firstly how quickly they regain the ball, it doesn't give the opponent any time to make any sequences of passes. And in my study of Inverness, they actually have some good technical players that can move the ball, but we never gave them an opportunity to do that.
"So defensively we were very strong, our pressing was excellent. And our attacking play was fantastic.
"I thought the two wingers were outstanding. Scotty Sinclair will be devastated he hasn't scored but you see an example at the end of how robust he is. He challenges with the boy (David) Raven and Raven bounces off him.
"He still has the power and strength to go again and he squares it and we end up getting a goal. Scotty and James were brilliant, both of them will be disappointed they haven't scored but real big contribution.
"Moussa will get goals. I'm pleased for him. There are other elements of his game that we work on in training that I see improving: how he receives it, his touch to move away into space is getting better.
"The captain was brilliant again in his pressing. The goal he scores, I think he was dumped on the floor a bit earlier in the move but he gets himself up there and gets his goal with a great finish.
"It was a very, very good team performance and I just feel we will get better as the season goes on."
Inverness manager Richie Foran admitted his side had been "totally outclassed by the better team."
"If you're to get any result against Celtic you need at least four or five of their players to have a real off day and you need our 11 at their best," he said. "That wasn't the case today, they had 11 players at their best.
"There's no stopping them at the moment. You can see the confidence running through their veins.
"They have pace, they break on you, they've got class, an abundance of quality, on the park, on the bench, and a manager who is doing a great job."