Sebastian Vettel made an encouraging start to his Ferrari career with the fastest time on the opening day of Formula One testing in Jerez.
The four-time world champion agreed a move to the Italian constructors after a disappointing final campaign with Red Bull, and looked immediately at home in Ferrari red.
Vettel completed 60 laps of the circuit and was quickest of the seven runners, topping the timesheets with one minute 22.620 seconds.
McLaren and Red Bull did not enjoy as much success as Vettel – the German's former team-mate Daniel Ricciardo suffering battery failure and issues with his power unit late in the session.
All eyes were on the Honda-powered McLaren as it debuted, but Fernando Alonso only managed six flying laps in a frustrating day.
Closely behind Alonso was the Ferrari-powered Sauber driven by Marcus Ericsson (1:22.777secs), the Swede making an impressive debut following his move from Caterham.
"It was a very good day," said Ericsson. "I think we have good reasons to be happy.
"We were able to complete a lot of laps, and we went through quite a few different small tweaks on the set-up and did all the installations needed.
"There were no major problems with the car, which was really the main thing. Overall it's been a good day, and I'm looking forward to the rest of the week. I hope we can continue like this."
World championship runner-up Nico Rosberg was most active on F1's return as he completed 157 laps in his Mercedes, but he had to settle for third place with a fastest time of one minute 23.106secs.
Valterri Bottas was also able to get some good laps under his belt in the new-look Williams, while Carlos Sainz was lapping nearly three seconds slower than Vettel in the Toro Rosso.
The testing session was notable by the non-attendance of Force India and Lotus, the latter only expected the feature on Tuesday after getting their car to the track late on Sunday.
