Nico Rosberg gave his Mercedes team reason to smile after recording the fastest time during day one of testing in Barcelona, despite having another disrupted day.
Mercedes' were plagued by problems during the first testing session of the year in Jerez and matters were not straightforward for the German outfit once more on Tuesday. Rosberg was only able to complete 14 laps in the morning due to a gearbox issue but was able to bounce back in a frantic final hour to top the charts with a time of 1:22.616.
The four fastest times of the day were all recorded late on as drivers found the Pirelli medium tyres to their liking.
Kimi Raikkonen was hot on Rosberg's heels, following up with a lap of 1:22.623 shortly after the German had put the W04 at the head of the field.
Third fastest for the day was Fernando Alonso, with the Spaniard making his first appearance in the Ferrari F138. Alonso (101) was the only driver to put in more than 100 laps and he, like many others, saved his best for last as he posted a time of 1:22.952 on the medium-compound tyres.
Sebastian Vettel's Red Bull had been fastest for much of the day, leading the way on harder tyres, but the defending World Champion was 0.349 seconds slower than the Silver Arrows on the medium tyres.
Having launched the FW35 in the morning, Williams wasted little time in getting a handy number of laps under their belt, with Pastor Maldonado (85 laps) putting the new model through its paces in impressive fashion.
Daniel Ricciardo was sixth for Toro Rosso, ahead of Sergio Perez's McLaren. The Woking outfit had a quiet day, with Perez focusing on long runs in the afternoon.
Paul di Resta and Force India also spent much of the day working on long runs as the Scot notched up the eighth quickest time.
Esteban Gutierrez's Sauber - which had brought out first red flag of the day in the morning due to a fuel systems problem - notched up a best of 1:25.124, just ahead of Max Chilton's Marussia.
Charles Pic in the Caterham was hindered by a technical issue in the afternoon and finished at the bottom of the charts.
Barcelona day one times:
1. Rosberg, Mercedes, 1:22.616, 51 laps.
2. Raikkonen, Lotus, 1:22.623, 40 laps.
3. Alonso, Ferrari, 1:22.952 102 laps.
4. Vettel, Red Bull, 1:22.965, 52 laps
5. Maldonado, Williams, 1:23.733, 77 laps.
6. Ricciardo, Toro Rosso, 1:23.884, 65 laps.
7. Perez, McLaren, 1:24.124, 68 laps.
8. Di Resta, Force India, 1:24.144, 75 laps.
9. Gutierrez, Sauber, 1:25.124, 60 laps.
10. Chilton, Marussia, 1:26.747, 65 laps.
11. Pic, Caterham, 1:27.534, 49 laps.