Barcelona F1 testing: Mercedes seals another 1-2 at end of week one

During the first half of the day, Bottas hustled his C5-shod Mercedes to a lap just three tenths shy of his pole position time in qualifying last year, cementing a particularly ominous Mercedes advantage.

Hamilton took the reins of the W11 for the afternoon and, while his best effort was also set on the softest tyre in Pirelli's range, the six-time champion was 0.784 seconds off his team-mate's benchmark.

The afternoon session added two further red flags to the morning's tally of interruptions, and was paused just after half an hour of running when Kevin Magnussen took a trip to the wall at Turn 8.

Magnussen suffered a right-rear puncture on only his fifth lap of the afternoon, spinning on the exit of the Barcelona circuit's seventh corner and ending up in the outside wall.

The Haas driver did not return for the rest of the afternoon.

Daniel Ricciardo prompted the second red-flag period, stopping on track on the run up to Turn 9 - Campsa - with an unspecified issue.

Renault was able to get Ricciardo back out for the final hour of running, although the Australian's particularly long run had been interrupted by the stoppage.

Ricciardo's team-mate Esteban Ocon completed the day third, as his morning time on the C4 tyre was beaten only by Hamilton in the afternoon, though he was ultimately 1.3s off Bottas's early pace.

Ocon and Ricciardo completed a total of 169 laps for Renault, the team's highest total during the opening week of testing.

Lance Stroll continued to underline Racing Point's impressive pace with a 1m17.338s - also on C4 tyres - completing 116 laps through the day, although his afternoon was dedicated to longer runs.

AlphaTauri's Daniil Kvyat was the next quickest, his best time also set on the C4 tyres, ahead of Antonio Giovinazzi - who was the most-travelled driver of the day having done 152 laps of the circuit.

Ricciardo beat Max Verstappen's best lap late on in the session, recovering from his stoppage and a late spin to sit seventh-fastest - with his best time set on the C3 rubber.

Gasly and Albon, taking over the AlphaTauri and Red Bull respectively for the afternoon session, completed the top 10.

Sebastian Vettel overcame his morning halt to set 100 laps, albeit with the 13th-fastest time, as Ferrari replaced his engine for the afternoon session.

Williams's Nicholas Latifi also triggered a red flag during the first part of running when his team detected an engine issue.

The Canadian received a new power unit for the afternoon, and he managed to complete 72 laps overall, half a second down on Lando Norris - who was conducting long runs on C1 tyres.

Magnussen, after spinning out, remained rooted to the bottom of the timesheets.

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