Racing Point's Lance Stroll feels his team has made good progress on the balance of its RP20, the Canadian also happy with his personal contribution to the improvements.
Stroll clocked in at the end of an uneasy day with the third best time, just 0.277s behind pacesetter Sebastian Vettel.
The 21-year-old endured a tiring day behind the wheel amid the changing conditions in the morning and the windy afternoon environment, but the Racing Point felt he'd put in a good workout overall.
"We put in a lot of laps – my neck’s going to be a bit stiff in the morning!" he said.
"We got held up a bit by the rain in the morning and it was really windy in the afternoon, which compromised running for everyone a bit.
"But all-in-all some solid running and the car felt pretty good out there.
"It’s testing, so we don’t know what everyone else is doing – but what matters is that we’ve been making progress over the past couple of weeks."
Beyond the good mileage, Stroll underscored the RP20's progress in terms of its all-important balance.
"We’ve definitely improved the car in terms of the balance on both short and long runs and the team have done a great job of dialling it in more and more as the days have gone by.
"It’s a bit weird having less time in the car compared to previous years, but I’d say this has been my best pre-season so far. I’m feeling fresh from all that off-season training and ready to go racing."
Racing Point performance engineering director Tom McCullogh said his team has furthered its understanding of its car which will run in the capable hands of Sergio Perez on the final day of testing at the Circuit de Catalunya.
"It was a bit of a difficult day, due mainly to the wet start and generally cold conditions," McCullogh explained.
"When the track did eventually dry out, the wind became particularly strong – the strongest it’s been in testing so far.
"Despite the strong winds, Lance did not put a foot wrong, thus maximising the available track time.
"In light of the weather conditions, we prioritised what was possible to achieve from our test plan, with some performance runs in the morning on the softer compounds followed by longer runs in the afternoon, which were unfortunately interrupted by red flags.
"Overall, a day of damage limitation in terms of productivity – but the car ran reliably and we’ve furthered our understanding of how to work with it, which is all valuable learning ahead of Melbourne."