The Frenchman's first race in charge was in Melbourne, but lurking nearby was the McLaren supremo Dennis, who has returned to the formula one paddock on a mission to rescue his beloved team that "lost its way" last year.
66-year-old Dennis will not wear a team uniform at the races and, during the pre-season, he insisted "he is not going to be on the pitwall", according to the Daily Mail.
But "What's the betting he will be (on the pitwall) before the season is over?" said correspondent Jonathan McEvoy.
Indeed, in Melbourne, Dennis was spotted walking to the pitwall, apparently to tell Boullier what to do.
"He was not (telling me what to do)," Boullier insisted to the Telegraph. "He came to visit a couple of times."
Dennis said he is just an observer at the races this year.
"I'm a racer, so the thought of not understanding and contributing doesn't come across my mind," he said. "When you observe things it's good to say 'why not this?' or 'why not that?'"
The bigger McLaren-themed story after Melbourne was the surprisingly good debut performance by rookie Kevin Magnussen.
But another F1 rookie, Toro Rosso's Daniil Kvyat, also caught the attention of the experts, like triple world champion Niki Lauda.
"These guys are, first of all, huge talents," he said.
The old guard is impressed at how the youngsters are arriving on the grid with almost no track testing and performing at the highest level.
Lauda says it's a generational thing.
"It's like my kids, who are four and a half and already better at computer games than me. They are made quite differently than in my day," he smiled.