Well, Mercedes certainly won the first day of Formula 1 2020.
Beyond that statement come all the usual testing caveats: it's the first day, fuel and ballast loads are unknown, the track will rubber in. All the fence-sitting hits, basically.
The headline takeaways are that Mercedes topped the morning running with Valtteri Bottas on a 1m17.313s, and then Lewis Hamilton marched on in the afternoon after taking over the W11 to bring the benchmark down to a 1m16.976s. In total, the duo completed the most laps on 173.