Nico Rosberg has laid down a marker to his rivals on the first morning of the second pre-season test while Manor Racing endured a frustrating session as Rio Haryanto suffered an oil leak at the Circuit de Catalunya.
The Mercedes W07 may have failed to top any of timesheets during the opening test last week, mostly due to the team remaining on medium tyres, but after effectively a whole race distance completed Rosberg strapped on the yellow-banded soft Pirelli tyres to blitz the times with a 1m 23.022s.
Such was the impressive nature of Rosberg's time, just two-tenths off Sebastian Vettel's top time from the first test on the ultra-soft tyres, it handed him top spot by almost two seconds from Ferrari's Kimi Raikkonen.
Raikkonen spent the majority of the session on the white medium compounds to hold second place from McLaren-Honda's Fernando Alonso. The Woking-based team had clearly shaken off its hydraulic and coolant issues which plagued its progress in the opening test as the Spaniard posted 50 laps, but did cause a premature end to the session with a red flag stoppage.
Further down the field Manor Racing failed to set a lap time after Haryanto suffered an oil leak after completing one installation lap and the problem prevented him from returning to the track until the final few minutes.
Having topped the times at the halfway stage Williams' Valtteri Bottas slipped down to fourth at the end of the session ahead of Max Verstappen who had unleashed Toro Rosso's updated car livery as the sun rose on the Barcelona circuit.
Nico Hulkeneberg, who topped the timesheet on his only day in the Force India VJM09 in the first test, had a low-key opening session with a best time of 1m 25.945s in sixth overall.
After initially setting the pace Daniil Kvyat also had an underwhelming morning and was held back by a right-rear brake fire midway through the session.
New team Haas continued to make steady progress as Esteban Gutierrez completed 23 laps and ended the opening stint eighth, ahead of Felipe Nasr who debuted the new C35 by gradually getting to grips with the new car. Renault's Kevin Magnussen once again banked a healthy number of laps without seeking outright speed to complete the morning running.