Bottas fastest on Day 6, headaches for Ferrari and Red Bull

Race simulations and tyre testing were the focus of Wednesday afternoon's pre-season testing at the Circuit de Barcelona-Catalunya, a session that saw an accident for Ferrari and engine issues for Red Bull.

None of the ten drivers at work after lunch came close to emulating the sub-1:20s times of Valtteri Bottas and Felipe Massa from the morning. The Mercedes driver's best time of 1:19.310s held on to the title of fastest lap seen so far in 2017, a tenth ahead of the Williams.

It was a quiet start to the afternoon with only five cars venturing out on track for brief runs in the first hour following lunch. It was the first time out today for Mercedes' Lewis Hamilton and Williams' Lance Stroll, while Sergio Perez (Force India), Carlos Sainz (Toro Rosso) and Kimi Raikkonen (Ferrari) picked up where they'd left off in the morning session.

Stroll had a much-needed trouble-free session, working diligently to improve his lap time over 59 trouble-free laps. He ended the day fifth fastest on 1:20.579s which was a tenth ahead of Hamilton's 1:20.702s. During his session, Hamilton spent 20 of his 79 laps in a single stint testing the durability of one set of ultrasofts.

Raikkonen was the cause of the day's first red flag, when the Ferrari went off into the gravel at turn 3 at the two hour mark. The cause of the accident was unclear, with Raikkonen reporting nothing amiss before the spin.

The impact with the tyre barrier resulted in damage to the front wing of the SF70H and to the left-front suspension, as well as minor damage to the left-rear. Raikkonen took no further part in the session, having run 53 laps up to that point.

• Gallery: all the pictures from Day 6

Red Bull was forced to change the engine in Max Verstappen's car over lunch, and the Dutch driver didn't get back out on track until shortly before the halfway point of the four-hour session. Verstappen was then able to run virtually a full race distance simulation, completing 58 laps without a problem.

However the RB13 then suffered an issue late in the run which forced Verstappen to pull off to the side of the track, triggering the second red flag of the day with 20 minutes remaining. The session did restart - with an extra five minutes on the clock - but was immediately thwarted by a final red flag caused by Marcus Ericsson's Sauber losing power and stopping at the exit of turn 8.

Earlier there had been a delayed start to the afternoon session for the perpetually beleaguered McLaren team. Fernando Alonso completed only 46 laps during the day, but team sources insisted there was nothing amiss and that it was all part of their pre-arranged programme for Wednesday.

Romain Grosjean in the Haas and Jolyon Palmer in the Renault also didn't put in an appearance until around the halfway point of the afternoon session, but again team sources indicated that this was all according to plan.

F1 testing resumes tomorrow morning at the Circuit de Barcelona-Catalunya at 09:00 local time. Make sure to follow our live coverage on our dedicated, as-it-happens page.

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