Toro Rosso's Albon follows Kvyat's lead - tops final morning session!

Alexander Albon picked up on Thursday morning where his team mate Daniil Kvyat had left off on Wednesday afternoon, the F1 rookie topping the time-sheet for Toro Rosso before the lunch break.

Albon's time - set on a Pirelli's softest available compound - was 0.148s clear of Renault's Daniel Ricciardo and 0.340s ahead of Mercedes' Lewis Hamilton, the German camp finally upping its testing pace in Barcelona.

Pre-season test Day 4 - Morning session

The Formula 1 paddock basked in crisp and cold temperatures when the final day of testing for Week 1 kicked off.

The usual permutations saw Lewis Hamilton strapped in the Mercedes, while it was Robert Kubica's turn to take to the track onboard the Williams FW42 and help the team make up some ground lost by the car's belated arrival at the Circuit de Barcelona-Catalunya.

The Polish driver got straight down to business when the light went green, heading out followed by McLaren's Lando Norris whose team lost a few hours in yesterday's session as a result of some overnight changes.

More aero assessments, measuring and data gathering were in order early on. But initial running was disrupted after just 15 minutes in when Norris beached his MCL34 at low speed at turn 5, the victim of an apparent strange failure.

Haas' Romain Grosjean was the first driver to put a significant time on the board, circulating in 1m19.905 and followed by Renault's Daniel Ricciardo.

Charles Leclerc took charge just after the one-hour mark, lowering the fastest time to 1m18.832. The Ferrari driver's spot at the top of the time-sheet lasted for the better part of 60 seconds as, lo and behold, Hamilton sprung to the top for the first time of the week!

The Brit put in a 1m800s on Pirelli's C2 compound that comfortably outpaced Mercedes' previous fastest time of 1m19.535 set by Valtteri Bottas on day 2.

Hamilton's supremacy also didn't last long, however, as Leclerc overhauled the Mercedes with a 1m18.475.

Mercedes were nevertheless definitely upping the pace, likely indicating they are entering a different phase of their development. The reigning world champion lowered the bar once again, and even several times, entering the 1m17 s with a run on Pirelli's C4 - or supersoft - compound.

That effort left Hamilton on top for about 20 minutes until Ricciardo - also on C4s - toppled the Silver Arrow with a swift 1m17.913.

Down at Williams, Kubica continued the team's laborious but necessary evaluation work, the FW42 running for most of the morning with the huge aero rakes.

Later stripped of these cumbersome devices, Kubica finally upped the pace as the session entered its final hour before the lunch break, the Pole lapping into the 1m21s and achieving a respectable 40+ lap count.

With just 30 minutes to go, Alex Albon took a leaf out Dany Kvyat's book of fast runs, popping his Toro Rosso to the top of the time-sheet with a mad dash on a set of C5 tyres that yielded a new benchmark time for the week of 1m17.637.

Yes, the C5s are Pirelli's softest compound; but that's still not bad for a young man driving an F1 car for only the second day in his career!

Meanwhile, Leclerc suffered a minor off, the Ferrari charger running wide at turn 5 but rescuing his car and avoiding a painful thump with the barriers.

The morning's lap count put the Monegasque ahead with 75 laps, followed by Grosjean with 65 and Hamilton who racked up 58 laps of Barcelona for his last stint at the wheel for this week.

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