It's easy to overlook the LMP2 category, with the quicker LMP1 prototypes hogging the headlines and the GT classes populated by readily identifiable super cars of the sort that fans can see on the road.
Nevertheless, LMP2 traditionally throws up some stern competition, and the Oak Racing Ligier-Nissan has been right in the thick of it this time. As I write this the car is seventh overall and leading the LMP2 fight.
Several things have struck me, most notably how alone the Oak car is on the track. Sure, Le Mans is an eight-mile-long circuit, but there haven't been too many retirements from this year's event so far and there are still 40-odd cars running.
Yet for much of the time I've been watching, Mardenborough has been charging around unhindered – which the team is probably pleased about – as the light ebbs away and the dark trees seem to close in around the circuit.
The second thing I noted was how dauntingly big the GT cars look when the low-slung LMP2 comes up to lap them. And how careful the LMP2 competitors have to be to negotiate the GTs but not get in the way of the blindingly fast LMP1 hybrids.
Other things that stand out: the aggressive way Mardenborough drives over the serrated kerbs; his commitment into Tertre Rouge on the first lap out on fresh rubber; the speed into the right-hand kink before Indianapolis; the blue lights that flash on the left of the cockpit when a faster car is trying to overtake and the 'fuel low' warning that flashes up on the telemetry in front of the driver when its time to make a pit stop.
Oh, and how quiet it all seems when he turns the engine off during a tyre change after the Nissan unit has been screaming away for a dozen laps.
I'm making sure I get up in time to catch the sun rising early tomorrow – it should be an absorbing time to ride on board at one of the world's greatest race tracks.