McLaren F1 team says downward spiral has now ended

Jenson Button qualified fifth for last Sunday's Brazilian Grand Prix and finished fourth after Williams's Valtteri Bottas was severely delayed at his second pitstop.

Button finished just 7.6 seconds behind the sister Williams of Felipe Massa, and Boullier said the improving performance of the car vindicated the extensive restructure he has undertaken since joining McLaren.

"I'm obviously very happy to be fourth, happy with the pace of the car, which is even better because we are faster than Red Bull and Ferrari so it's good," Boullier told AUTOSPORT.

"Austin was not as clear as Sochi and here, but clearly pace-wise we have closed the gap.

"Not enough, but at least the momentum is back.

"The spiral is up again and not down."

McLaren has a major upgrade planned for the season finale in Abu Dhabi, featuring a new aerodynamic concept led by the team's new chief engineer Peter Prodromou.

"Every development we have done since the summer is applicable on next year's car, so it's a whole concept I have pushed very hard for to ensure it went through," Boullier added.

"We have improved the car this year, which is very good, and everything we have learned will benefit next year's car, which is also very good."

McLaren lies a clear fifth in the constructors' championship after Brazil, but Boullier reckons the team will need some luck to overhaul the 39-point gap to Ferrari in the double points Abu Dhabi finale, despite the increasing competitiveness of the MP4-29.

"It's going to be difficult. We need both drivers to finish in front of the Ferraris and even if we take some good points it is still a lot of points to catch up," Boullier said.

"We need a very lucky race in Abu Dhabi but we will try our best."