Celtic are due to travel to Ibrox for their last-16 tie next Saturday – although the match may be moved given the funeral of Prince Philip, Duke of Edinburgh, will take place at 3pm on the same day – and Kennedy is confident after their biggest league win of the season.

"It was good," said Kennedy, who hopes Forrest will recover from the back and hamstring niggle which saw him replaced by Christie.

"It has been building blocks for us in recent weeks in terms of building up performance.

"We know if we are on our A game we can cause Rangers huge problems, so it is a good game to come out of with scoring goals and having that extra bit of confidence.

"We can hopefully take it into next week and win that game."

After good performances in the last two matches against Rangers which ended in a defeat and a draw, the former Celtic defender is keen to go one better against the newly-crowned Scottish champions.

He said: "There always is (something to prove). I think last time we did in terms of performance, but now it is all about getting a result next week.

"I felt this coming for the last few weeks. I thought we were going to score a few goals and give someone a bit of a hiding, but today was a great example of that in terms of putting a performance in and putting it all together."

Forrest, making his first Premiership start since September after recovering from ankle surgery, was taken off just before the hour mark, but Kennedy revealed a different problem.

He said: "It is too early. We will just have to assess him. He kind of stiffened up around his back and hamstrings around the start of the second half, so it was a case of not taking any risk with him. Hopefully we got him off quick enough.

"It is a different area (from the ankle) and, with players coming back after so long, you do get niggles and stiffness which are hopefully just a day or two in passing. I don't want to say too much."

Livi boss David Martindale's initial anger gave way to disappointment as he praised the home side.

He said: "I am disappointed. I was angry after the game and in the changing room, now I'm disappointed.

"I felt there was an acceptance out there, we accepted that and that is not what I want from my players. We need to work on that.

"On the flip side, and I am not trying to sugar coat it, I thought Celtic were fantastic.

"Obviously we allowed Celtic to be fantastic, but I do think they popped the ball really well.

"There was a hunger and appetite with Celtic with the way they moved the ball I have not seen for a while and they looked like a team who were playing for the manager.

"If John has any chance of the job that will have done him the world of good. I think you can see the players were playing for John and they were enjoying it."