An encouraging start for McLaren in the opening 40 minutes: the MCL32 is already up to 10 laps with Vandoorne - it took them rather longer to hit that mark last week!
For no-one is this test more critical than McLaren and, in particular, their engine supplier Honda.
The first test, frankly, dismal for them, with reliability problems compromising running and raising the spectre of a fundamental problem with the redesigned Honda 2016 engine.
Honda’s F1 boss Yusuke Hasegawa admitted to being “worried” by the engine failure. Honda did not know what caused it at the time, and have only said since that investigations are ongoing.
McLaren racing director Eric Boullier was not much more encouraging. “Can we get back on track with what we’ve expected? I don’t know. We have to investigate what is wrong.”