McLaren racing director has praised Stoffel Vandoorne for the improvement he's shown over the course of his first season in Formula 1.
Boullier has been critical of the young Belgian in the past. He previously suggested that Vandoorne hadn't lived up to the team's expectations and needed to change his driving style.
But such complaints couldn't be further from Boullier's now, heading into the final four races of 2017. Vandoorne finished in the points in Singapore and Malaysia, beating his team mate Fernando Alonso in the process.
"Stoffel has learned a lot and he's now doing an excellent job," Boullier told French broadcaster Canal Plus this week. "He is completely confident in himself and is always gaining more experience.
Boullier added that he understood how difficult the initial transition into Formula 1 had been for the 25-year-old.
"He was at the centre of the attention of the press and spectators as he became the team mate at McLaren of a world champion," Boullier pointed out.
"Everyone who made their débuts in recent years, including Max Verstappen, went through several difficult months before they began to reveal their potential," he continued. "But it was less noticed."
Unfortunately Vandoorne's Japanese Grand Prix didn't quite go so well, after he made contact with Ferrari's Kimi Raikkonen on the opening lap.
"Stoffel’s race was compromised at turn two, when he was pushed down the order after being hit by Kimi," Boullier explained. He praised the driver for continuing to push hard for the remainder of the race.
"The Japanese Grand Prix for us was not such a great success," Vandoorne himself admitted in a short video message posted on Twitter.
"Unfortunately our race got compromised in the first corner already with the touch," he said. "I don’t think it was intentional, it was just cars being in the wrong places at the wrong time.
"I fell to the back, and drove my own race to the flag," he reported. "Pretty much a race to forget for us, but that's the way the racing goes sometimes.
"Nonetheless Suzuka is a very special place. It’s just a shame we couldn’t get a good result for all the thousands of fans in the grandstands.
"The last races were positive for us, and I think the team has done an amazing job," he pointed out. "They really deserve a bit of a break now [until Austin]. We should be ready for the final four races of the season.
"Hopefully we can have a couple of good races left."