Mercedes' Valtteri Bottas led the way from Ferrari driver Sebastian Vettel on the opening morning. "It was a bit tricky with partly very windy conditions out there but for sure much better conditions than last week". The world champion was using the soft tyres and set a time 0.412s off Vettel's best.
Issues relating to the battery and hydraulics caused the Woking based team to lose valuable time as they tried to solve the issues, but despite the breakdowns, Boullier says the team is not too concerned by the problems and that these troubles are expected to come during testing.
McLaren managed to get Vandoorne out again just before the chequered flag ended the morning session, giving him a total of seven laps, while Vettel, Bottas and Verstappen all did more than 80.
While most teams were progressing with their timetables, it was McLaren who endured a frightful day, as Stoffel Vandoorne began with an installation lap that saw the Belgian return immediately back to the pits to correct a battery failure caused by the power unit.
Vandoorne, with one flying lap to his name, had just set personal best first and second sectors before coming to a halt exiting the final corner with a battery-related problem to blame.
Vandoorne stopped at turn three shortly before 4pm and never returned to the track.
Out of McLaren's five test days this year, the car's running has been restricted by reliability issues on three and a further day was lost to poor weather last Wednesday.
The American tried to put on a fearless face, but he will be concerned by what he has seen so far this winter with just three further days of testing before the season gets under way in Melbourne on March 25.
It was a productive morning for Mercedes, Ferrari and Red Bull with the trio clocking up more than 80 laps apiece. "Those problems could have affected any of the three teams, so of course it's an issue for us. It's the right thing to do, we have found some that are not fit for objective and that's great".
The Red Bull issue was one of four red flag stoppages, with one for debris and the other two due to Stoffel Vandoorne's McLaren.
The Honda-powered Toro Rosso was fourth fastest. But a brake problem meant that the second driver, Brendon Hartley, could not take over duties in the afternoon, which meant that Toro Rosso's day was over. Gasly still finished fifth in the standings at the end of the day.
On a competitive day as no driver dipped below the 1m20s mark, Kevin Magnussen was also within a second of the overall pace in sixth place.