MONTMELO, Spain -- McLaren started the second week of Formula One's pre-season testing with the fastest time, after Lando Norris set a 1:17.709 in the final hour of the afternoon session.
The time was 0.4s shy of the best lap from last week's test and put McLaren at the top of the timesheets for the first time this year. It coincided with McLaren's former driver Fernando Alonso visiting the paddock for the first time since he walked away from F1 last year.
Norris set the time on the C4 tyre -- the second softest compound in Pirelli's range -- compared to the C5 used for the fastest Nico Hulkenberg's fastest time last week. The lap moved Norris 0.006s ahead of Red Bull's Pierre Gasly, although the RB15 set its time on the harder C3 tyres.
"We pushed a little more today, but really it's all about understanding how the car works," Gasly said. "The pace was good, but we just have to focus on ourselves and work through the programme we've defined for each day.
"So far it's been positive; we've managed to get through our plan and we've gained a lot of mileage. The potential is there so we'll just try to improve in the areas we can, keep our heads down and keep working."
Shortly after setting the time, Norris stopped on track between Turns 2 and 3, resulting in the third red flag of the day. One of the earlier red flags was also caused by Norris when his car lost hydraulic pressure at Turn 3 and the other was caused by Valtteri Bottas' Mercedes stopping on track with a loss of oil pressure, which resulted in a lengthily engine change and limited the Finn to just a handful in the afternoon.
It was another underwhelming day for Mercedes despite a new aerodynamic package arriving at the track on Tuesday morning. The updates feature changes to the nose, front wing, barge boards and sidepods that the team hopes will close the gap to Ferrari from the first week. Lewis Hamilton completed 80 laps in the morning without issue but the problem in the afternoon occurred on Bottas' second lap out of the pits and cost him somewhere in the region of 70 laps of running. He went on to complete seven laps in total, including a 1:20.167, which moved him ahead of Hamilton and up to 11th overall.
"It was not exactly the day we hoped for, running for the first time with the bodywork kit that we expect to use in Melbourne, with a large part of the day lost to an oil pressure issue at lunchtime," Mercedes technical director James Allison said. "Nevertheless, either side of that problem we did do some useful things, finding that the car behaves a little differently with the new package. We're looking forward very much to have a trouble-free day tomorrow to get a better feel for what it can do."
Ferrari also suffered its first major stoppage of testing after checks to the cooling system in the morning limited Charles Leclerc to 29 laps. Sebastian Vettel added another 81 laps in the afternoon without any major issues, setting the fourth fastest time overall while running the C3 compound tyre.
Vettel set his fastest lap at roughly the same time of day as Gasly in the Red Bull, on the same tyre compound and over similar length of run. Gasly's 1:17.715 is the fastest lap we've seen on the C3s during pre-season and came on a short five-lap run that alternated between push laps and cooldown laps, similar to a qualifying run. Vettel was also on the C3s for a five-lap run and clocked his 1:17.925 on the first of his flying laps to set Ferrari's fastest time of the test so far. He went on to test the C4 compound for the first time this year, but appeared to be on heavy fuel and set times some way off the pace.
"It was a busy afternoon, but it was good to make u p for the laps lost in the morning," Vettel said. "We are still trying to understand the car, trying various set-ups. This afternoon, we also had a first go with the sup ersoft compound, just to get some more information. The next couple of days will be import ant for us".
Alfa Romeo, Toro Rosso and Haas all set times in the 1:18s on the C4 compound, while Renault appeared to focus on heavy fuel runs again with times in the 1:20s -- nearly three seconds off their fastest lap from week one. George Russell clocked a 1:19.662 -- the fastest the Williams has gone since it hit the track last Wednesday -- and completed 119 laps in total.
"It feels like a proper day one for us really," Russell said. "Great to get some laps on the car, just understand a bit of low fuel, high fuel, what the car's doing, and gives us an indication of what to do the rest of the week.
"It certainly hasn't made up for last week as everybody else at this stage is fine tuning the balance whereas we're needing to understand the car, but I feel we're at a good spot, the car isn't in the perfect window right now but I feel like it's definitely got the potential and we've still got three days ahead of us to do that."
Testing continues for the rest of the week before teams finalise their packages for the opening race of the season in Australia next month.
Times at close
1. Norris, McLaren, 1:17.709, 80 laps (C4)
2. Gasly, Red Bull, 1:17.715, 136 laps (C3)
3. Stroll, Racing Point, 1:17.824, 82 laps (C5)
4. Vettel, Ferrari, 1:17.925, 81 laps (C3)
5. Giovinazzi, Alfa Romeo, 1:18.589, 99 laps (C4)
6. Albon, Toro Rosso, 1:18.649, 103 laps (C4)
7. Leclerc, Ferrari, 1:18.651, 29 laps (C3)
8. Magnussen, Haas, 1:18.769, 131 laps (C4)
9. Russell, Williams, 1:19.662, 119 laps (C5)
10. Ricciardo, Renault, 1:20.107, 77 laps (C3)
11. Bottas, Mercedes, 1:20.167, 7 laps (C2)
12. Hamilton, Mercedes, 1:20.332, 83 laps (C2)
13. Hulkenberg, Renault, 1:20.348, 80 laps (C3)
(Tyre compounds in brackets C1-C5, hardest to softest)