The Hoops midfielder took his campaign tally to 15 on Sunday with the only goal of the match against Inverness at the Tulloch Caledonian Stadium which extended the champions' unbeaten run in the league to 18 games.
Commons, 30, is top scorer at Parkhead and the clever one-two he played with Georgios Samaras in the second minute before he rifled a shot low past Caley goalkeeper Dean Brill was arguably the best move of a match which failed to live up to its early promise.
The Nigeria defender said: "Everything is going right for Kris at the moment. He is one of the best players we have and he is helping the team a lot.
"We are lucky to have him when he is in this shape.
"Last year he did well, but this year we are relying on him to get something.
"Coming from midfield, nobody really understands how he plays, he is not a striker so you can't just mark him.
"That is why it is difficult for teams to keep Kris out when he is in his best form."
After winning 7-0 at Hearts and 5-0 at Motherwell earlier in the month, the champions ground out their third 1-0 scoreline in four games against Caley.
Ambrose believes opposition sides have tightened up against the Parkhead men, who are 11 points clear of second-placed Motherwell.
"Teams watch us and see how we play," he said. "They try to sit back and make it difficult for us to play or create chances.
"They try to sit back and rely on counter-attacks or set-pieces.
"We knew it was not going to be easy, we have gone to Inverness many times and it has been difficult.
"Also, the state of the pitch yesterday was not very good for the style of our play so we had to adapt quickly."