- Sebastian Vettel makes first appearance in new Red Bull at Jerez
- German driver aiming to win a fourth world title in succession
- Ferrari's Felipe Massa tops the fastest lap charts ahead of Mercedes' Nico Rosberg
Sebastian Vettel revved up his engine for the first time this winter as he started preparations to claim a fourth successive world title.
The German, who became the youngest triple world champion last season, completed over 100 laps at Jerez as Red Bull continued its testing period in Spain Thursday.
Vettel, 25, clocked the third fastest time of the day behind Ferrari's Felipe Massa and Mercedes' Nico Rosberg after coming home in one minute 19.052 seconds.
"So far, I think we can be pretty happy," Vettel told reporters ahead of the season-opener in Melbourne on March 7.
"(Teammate) Mark (Webber) had a good couple of days to start with and I took over today. It was great to get back in the car, to get rid of the rust and to get back in the groove again.
"At this stage it's very difficult to judge anything else. It could be that there is a favourite after these three tests, but it could turn out to be completely different in Australia because it's a different track with different characteristics.
"I expect the championship to be at least as tight as last year, as the regulations haven't changed so much."
Lotus' Kimi Raikkonen finished fourth fastest and the Finn revealed he was delighted to get to grips with the team's new car.
"It was good to get behind the wheel of a Formula 1 car again," he told the team's official website.
"The E21 feels quite good so far, even if the balance isn't quite to my liking yet. That didn't stop us going through the program we wanted to do which had a lot of aero runs in it.
"We know the car can go faster, we were just running through what we needed to achieve.
"It's a shame that we had a clutch issue at the end of the day, but that's why we come testing so we can find these problems and fix them."
The most noteworthy incident of the day occurred when British driver James Rossiter was involved in an accidental collision with one of his Force India mechanics, who thankfully escaped any serious injuries.