First-time Mercedes runner Nikita Mazepin topped the timesheet on the final and second day of the F1's in-season test in Barcelona.
The 20-year-old Russian put in a 1m15.775s that was just over two tenths of a second shy of Valtteri Bottas' Tuesday performance but which comfortably edged Toro Rosso's Alex Albon and Ferrari tester Antonio Fuoco who completed the top three.
Charles Leclerc - running in Ferrari's Pirelli car - was fourth in Tuesday's running while Alfa Romeo's Kimi Raikkonen rounded off the top five.
Barcelona in-season test - Day 2
|12||Stroll||Racing Point (Pirelli)||1:20.745||119|
With the exception of Racing Point and Williams, all teams executed a driver change for the second and final day of in-season testing at the Circuit de Catalunya.
British hopefuls Dan Ticktum and Jack Aitken were on duty for Red Bull and Renault while McLaren split the day between Oliver Turbey and F2 racer Sergio Sette Camara.
Over at Ferrari, Antonio Fuoco was behind the wheel of the Scuderia's SF90 but like yesterday the Italian outfit also supplied a second car - steered by Charles Leclerc - devoted to Pirelli's 2020 tyre development programme. But the main attraction was the presence on board's Mercedes W10 of young Russian Nikita Mazepin.
Haas' Kevin Magnussen was the fastest runner in the morning session although the Dane's 1m18.101s was over two seconds slower than the fastest lap achieved by Valtteri Bottas on Tuesday.
The Dane clocked at lunch time just ahead of Ferrari's Fuoco and Toro Rosso's Alex Albon.
Red Bull's Pierre Gasly suffered a transmission issue on Tuesday and thise problems appears to persists on day 2, with Ticktum missing the first hour of running and then pulling to the side of the track at Turn 10 sixty minutes into his running.
Two additional red flags were triggered during the morning by Williams' Nicholas Latifi and by a spin at Turn 12 by Mercedes' Mazepin.
The start of the afternoon saw the Russian Formula 2 racer undertake a series of performance runs, the last of which included a flyer on Pirelli's C5 rubber that enabled Mazepin to secure the fastest lap of the day.
Albon's best effort was also achieved towards the end of the session, the Toro Rosso C5-shod charger beating Fuoco to the overall runner-up spot.
Renault's Jack Aitken concluded his day P6 while Magnussen's morning lap put the Dane 7th at the end, just ahead of Nicl Yelloly who completed a trouble-free second day of running with Racing Point.
Williams' Latifi and Ticktum completed the top ten, with Turvey, Stroll and Sette Camara following behind.
The young Brazilian only managed 19 laps in the afternoon as the result of a mechanical issue that forced the McLaren rookie to park his car and bring out the only red flag of the afternoon.