Lewis Hamilton breaks down in Formula 1 testing
Lewis Hamilton suffered an engine failure that cut his running to just a handful of laps on the penultimate day of Formula 1 pre-season testing.
The world champion's car had what Mercedes described as "an oil-pressure anomaly, which made the engine shut down as a precautionary measure".
Investigations into the cause meant Hamilton did not get back out on track.
Red Bull's Max Verstappen had an eventful day, losing control twice to take his spins to six in five days.
Verstappen blamed his own error and the difficult windy conditions for the incidents.
The Dutchman lost control at the chicane and Turn Five and has now had three times as many spins as any other driver in the five days of testing so far.
Ferrari's Sebastian Vettel also had a spin, but ended the day fastest, despite his off at Turn Five, setting a one minute 16.841 seconds best.
That is still more than a second slower than the fastest time of pre-season so far, set by Hamilton's team-mate Valtteri Bottas last week.
Headline lap times in pre-season testing are a notoriously unreliable indication of actual competitive form because the teams do not reveal the specifications in which they are running their cars and engine modes, fuel loads and other settings can make a significant difference to lap times.
The high number of spins by Verstappen has raised questions about whether the Red Bull is suffering from an instability on corner entry.
But Verstappen said he had simply not seen a patch of water on the outside of the track when he lost control entering Turn Five.
He said: "I think I just touched the white line and it was still a bit of a damp patch. I didn't see it in the car but I looked back at the footage and on the onboard afterwards I saw it."
As for his earlier spin at the chicane later around the lap, he said the car had been unsettled by the windy conditions: "It depends on the weather sometimes. Today and also yesterday it was very windy and all the cars are struggling in those conditions.
"Overall I am very happy because I think we are always improving but we had some good laps and it won't be like this all season. We have things we can work on and we will continue on that."
Red Bull introduced a major aerodynamic upgrade on to the car on Thursday, with a new front wing, under-nose 'cape', aerodynamic deflectors behind the front wheels and rear diffuser.
Verstappen said he had no idea where Red Bull stood compared to Mercedes and Ferrari in the competitive order.
He said: "Overall we need to step up, and we are working on that. So far this year the car is definitely an improvement, and it also has to be if you want to fight for the championship. We just focus on ourselves, and then we will find out in Melbourne where we are."
In addition to Verstappen's two spins on Thursday and two on Wednesday, in addition to his two on the first day of last week's test, Vettel has lost control on each of the two days of running this week.
The German joined Verstappen in spin at the slow, long-radius, downhill left-hander of Turn Five, where Mercedes' Valtteri Bottas also ran off track but avoided the barriers. Vettel lost control on the exit, while Verstappen and Bottas' incidents were on the entry.
Alfa Romeo's Antonio Giovinazzi also had a spin, damaging his rear wing when he lost control at Turn Four.
Fastest times, second pre-season test, day two:
1 Sebastian Vettel (Ger) Ferrari 1:16.841 U
2 Pierre Gasly (Fra) Alpha Tauri 1:17.066 U
3 Lance Stroll (Can) Racing Point 1:17.118 M
4 Nicholas Latifi (Can) Williams 1:17.313 S
5 Lando Norris (GB) McLaren 1:17.573 H
6 Max Verstappen (Ned) Red Bull 1:17.738 H
7 Valtteri Bottas (Fin) Mercedes 1:17.985 M
8 Esteban Ocon (Fra) Renault 1:18.013 S
9 Kevin Magnussen (Den) Haas 1:18.225 S
10 Alexander Albon (Tha) Red Bull 1:18.393 H
11 Daniel Ricciardo (Aus) Renault 1:18.395 M
12 Antonio Giovinazzi (Ita) Alfa Romeo 1:19.670 M
13 Lewis Hamilton (GB) Mercedes 1:22.425 M
Key: U = ultra-soft tyre; S = soft tyre; M = medium tyre; H = hard tyre