The £7m defensive signing, 26, has started the past five games - all wins - but was left out of some early-season matches, including the Champions League qualifying loss to CFR Cluj.

"I was just not ready for this moment," Jullien said. "It's as simple as that. I was feeling sharper. It's the choice of the coach and you have to deal with it. I respect that 100%."

Jullien described his Old Firm derby as "perfect" after marshalling the Celtic defence in Sunday's 2-0 win against hosts Rangers.

That put Neil Lennon's side three points clear of their Glasgow rivals with a 100% record in the Scottish Premiership.

Celtic will face Cluj again in the Europa League this autumn, after the Romanian side lost their Champions League play-off, with Rennes and Lazio also in Group E.

"It was a really, really long month and there were a lot of games," Jullien said of Celtic's start to the season. "All the guys deserved a trophy because we did a really good job on the field.

"The intensity, the level, I really like it.

"It is just one month. Neil Lennon is the one who believes in me. He told me I don't have to panic and just to be sure of my talent."