Nico Hulkenberg posted the fastest time of the entire week of testing, 2 hours before the end. The Renault driver improved Albon's earlier time by nearly 3 tenths, removing some of the doubts that surround the R.S.19.
The afternoon session on the final day of Test 1 saw quite a few different drivers in the car. At Williams, Robert Kubica switched seats with George Russell. Magnussen took the wheel of the Haas VF-19, Bottas ran the Mercedes and Hulkenberg replaced Ricciardo at Renault.
Gasly was out quickly, and started off with a strong run on C2 tyres, the white marked tyre that has been mostly used in afternoon sessions to enable longer runs. A few minutes after that stint, he was already back out on track on the yellow C3 tyre.
McLaren were looking into a similar run plan, though Norris's car was quite unstable at the rear, particularly under braking and turn-in to the chicane. The MCL34 also seems pretty hard sprung, bouncing hard on the kerbs, very much in contrast to the RB15 which seems very stable on the kerbs of the slowest section at Circuit de Catalunya.
A bit later, Ferrari's Leclerc and Red Bull's Gasly did comparable runs on C3 tyres, with Gasly clearly faster in the beginning, followed by a sharp drop-off in pace. The RB15 however still averaged better at 1m22.5s, as the Ferrari averaged around half a second slower.
Half an hour later, both were again involved in comparable runs on the same tyre. This time Leclerc's average was better - 1m22.5s, while Gasly's was 1m22.7s if you omit the cooldown lap he did after pushing on the first one. Considering Gasly's first lap was 2.4s faster than Leclerc's, that illustrates how much sharper his drop-off was for the second stint in succession.
Lando Norris had meanwhile switched to the hardest C1 tyre while Giovinazzi was also pretty busy, mainly on the yellow C3 compound.
While most cars did longer runs, Hulkenberg record the fastest time of the session, and in fact of the entire test thus far. Albon's first sector is faster and Ricciardo's middle is also faster, but Hulk's lap combined to beat them.
Nearly exactly one hour later, Giovinazzi stopped out on track, causing a red flag and an early end of the test.
This saw Hulkenberg take the top spot for today, ahead of Albon and Ricciardo, both of whom had set their best times in the morning session.