McLaren finally got its pre-season testing program underway as Jenson Button topped the times on day two at Jerez.
The Woking based squad encountered issues with the new MP4-29 which prevented any running on Monday.
However, the team made up for the lost ground as Button completed 43 laps, setting a session best time of 1m24.165s, which was almost 0.7s quicker than his rivals.
The result came shortly before the team confirmed former Lotus team principal Eric Boullier will join McLaren as racing director for the 2014 season. The Frenchman left his post at Lotus last week.
Ferrari continued their impressive start to testing with Kimi Raikkonen setting the second fastest time in his 47 lap stint in wet conditions at the former Grand Prix venue.
A damp morning had seen Pirelli elect to bring forward its wet weather testing program from Friday, with water trucks dispatched onto the circuit prior to the first cars going out.
The track began to dry as the session progressed and by the afternoon slick tyres were used.
Sauber's Esteban Gutierrez made the change first but the slippery conditions caught him out. Luckily he escaped from his trip to gravel trap unscathed.
It was a good day for the Mercedes powered cars with Williams third quickest in the hands of Valtteri Bottas.
After the front wing failure with Lewis Hamilton on Monday, Mercedes were fourth with Nico Rosberg behind the wheel.
The W05 completed more running than any other car on the day, ending proceedings with 97 laps to its credit.
Force India completed a good day for Mercedes powered cars in fifth with Sergio Perez.
In stark contrast, the Renault-powered cars struggled for mileage with the Red Bull and Caterham completing 19 laps between them.
World champion Sebastian Vettel completed just eight laps to add to the three he managed on the first day of testing.
With two and half hours remaining of the session the team called an end to his day with a “power storage issue”.
Renault's problems also prevented Red Bull's junior team, Toro Rosso, from completing any running.
Daniel Ricciardo will take over from Vettel for day three for his first competitive appearance with the Red Bull squad.
The Caterham of Marcus Ericsson completed only 11 laps and, to make matters worse, stopped on track bringing their day to a premature end.
Testing continues on Thursday, where the Marussia is expected to be seen for the first time.