McLaren racing director Eric Boullier played down the significance of the British team's problems after mechanical issues blighted their test session on Tuesday.

Stoffel Vandoorne would cause two of the three red flags and had to be pushed down the pit-lane on a third occasion as electrical and hydraulic failures hit the MCL33 in Barcelona, resulting in just 38 laps of running.

The poor reliability brought back flashbacks of a year ago, something the change from Honda to Renault engines was meant to stop, but Boullier insists it is just part and parcel of this stage of the year.

"There is absolutely no drama," the Frenchman told Sky Sports. "This is just testing. We push the car to the limits and we try some various conditions and set-ups and things. Sometimes it works, sometimes it doesn't.

"The cars are complicated and when you have to change something in the heart of the car it takes longer than in the old days when it was much simpler."

On Wednesday, that notion had seemed to be true with Fernando Alonso running well in the first hour and a half with the most laps of anyone, but another stoppage interrupted that strong start as McLaren now looks to play catch up.

"There are important parts [to test] and less important parts and we'll do our best to cover the most miles we can in the last three days," Boullier added.