Montreal (31-19-8) started the season 13-1-1 but has gone 18-18-7 since. The Canadiens, who lost their last game under Therrien 4-0 at Boston on Sunday heading into a five-day break, play the Winnipeg Jets at Bell Centre on Saturday (2 p.m. ET; CBC, SN, TVA Sports).
READ: Claude Julien impact
Montreal is 1-5-1 in its past seven games, but Julien was not dwelling on that.
"You know, we're in first place, so there's no need to panic, there's a need to fix," Julien said of the Canadiens, who lead the second-place Ottawa Senators by four points in the Atlantic. "So we're not panicking. We're going to fix things so that we can get back on the right track and we're going to start winning again. And that's where the focus has to be for myself as a coach and for them as players."
This is the second time Julien has replaced Therrien with the Canadiens; he made his NHL coaching debut with Montreal after Therrien was fired during the 2002-03 season. Julien was fired in January 2006.
"It kind of felt like a new season," goaltender Carey Price said of practice Friday. "It definitely had that vibe."
The Canadiens have been shut out in three of their past five games.
"I think our team wasn't responding," Price said. "We weren't playing with as much enthusiasm as maybe we should have been, so that definitely woke everybody up. You saw the energy that we had in practice today and that was a good thing."
Price was asked if the Canadiens were no longer responding to Therrien.
"A little bit, I don't think the guys were playing with a lot of confidence either," Price said.
Sunday was the first time Price faced Boston without Julien as Bruins coach. The winningest coach in Bruins history, Julien was 419-246-94 in 10 seasons in Boston and won the Stanley Cup in 2011 and the Presidents' Trophy in 2014.
"They had a winning recipe, so that's definitely something to be excited about," Price said. "They always seemed to play well structurally and they always seemed to play with possession a lot of the time."