Red Bull's Daniel Ricciardo finished the day third on the timesheet, but development is more important than outright speed at the end of a testing day.
The Aussie was satisfied with conclusion of his programme - especially on the aero dynamic front - despite suffering an engine failure which took deprived his schedule of mileage.
"It was a good outing for the aero department – we did a lot of data gathering in the first hour, which all went to plan, and that’s important for the guys, even though for a driver it’s not the most thrilling thing, as you’re just trundling around really!
"After that we did a few runs on the soft tyre and made a few mechanical changes, which were interesting, we then completed a couple of runs on the supersoft.
"I think we discovered a few things there. You do try some bigger set-up steps than you might do on a race weekend and it was interesting to see what the results of those changes were.
"We were planning a few long runs in the afternoon but obviously the power unit issue prevented that."
Tomorrow, Max Verstappen will take over the RB13 which will be fitted with a new Renault power unit for Wednesday's session.
GALLERY: All the action from the Day 1 in-season testing at Bahrain
Keep up to date with all the F1 news via Facebook and Twitter
Max Verstappen’s racing curiosity has never been confined to Formula 1 – and now, one…
When F1’s radically redesigned 2026 cars finally roll out in Barcelona at the end of…
Max Verstappen has never been one to sugar-coat reality – and as Formula 1 braces…
Ferrari have survived decades of criticism about strategy calls, driver politics and pit stops that…
While the paddock has been whispering for months that Mercedes might be holding the winning…
Dan Gurney passed away on this day in 2018, and here at F1i we'll never…