McLaren believes wins are possible during 2014 F1 season

Since finishing second and third in the Australian Grand Prix, McLaren has scored only 10 points in the next three races, culminating in its dismal run to 11th and 13th in China.

But racing director Eric Boullier is confident about planned upgrades for the Spanish GP and subsequent races that will allow it to tackle its downforce deficit.

"We have to believe we will win a race," said Boullier.

"A lack of downforce is obviously hurting us when we have very hot track conditions, or very cold like we had in China and there is a technical reason for that.

"What is happening in the team is [making us] very confident and we will be able to keep pushing on a very aggressive and strong development [path] through the whole season.

"We will put ourselves in a position, maybe not in the first part of the season, but maybe later, to fight for a win."

Boullier stressed that the team will not use the imminent return of Honda as engine supplier for 2015 as an excuse to write off the season.

He also pointed out that the team cannot allow itself to plumb the depths it did last year, when it had only 23 points after four races compared to its current haul of 43 and went on to finish only fifth in the constructors' championship.

"You cannot afford to let yourself think that way in motor racing," he said.

"The 2013 season should be a benchmark year for us never to do it again.

"2014 should be seen not as a transition year, but of rebuilding a winning team.

"We have this extra challenge to work very efficiently with our partner Mercedes, but later in the year to start to implement the Honda arrival."