Sebastian Vettel believes Lewis Hamilton can still be a contender for this year's Formula One world title.
After a troubled opening two days of testing for Hamilton's Mercedes team, there were smiles all round yesterday as Nico Rosberg ran for a punishing 148 laps - the equivalent of two grands prix distances.
Rosberg ultimately finished second on the timesheet at the end of the third of four days this week at the Circuito de Jerez with a lap of one minute 18.766secs.
The 27-year-old German found himself sandwiched between pacesetter in Ferrari's Felipe Massa and three-times world champion Vettel on his maiden outing in the new Red Bull.
Massa posted the fastest time of the week so far with a 1:17.879 - albeit on the faster, soft tyres - with Vettel 1.2secs adrift.
With Rosberg finally proving the Mercedes can be reliable, after an electrical fault curtailed his running on Tuesday, whilst Hamilton crashed following a rear-brake failure on Wednesday, there may yet be hope for the 28-year-old Briton.
Asked whether Hamilton could challenge for the championship, Vettel said: "Yes, of course.
"The way least season started with a lot of different teams and drivers winning races, there's nothing that speaks against that happening again this year.
"The regulations haven't really changed, and at some stage I think it will get even closer at the top and so everyone is in the hunt.
"We saw last year Williams set some highlights, winning in Barcelona - not because they were lucky but because they were fast.
"Even if after the last Barcelona test you have a certain favourite, it could all be different in Australia."
Vettel was happy enough with his own return behind the wheel just 74 days after he clinched his third successive crown in Brazil towards the end of November.
"We certainly hit the targets, with many laps," added Vettel, who completed 102.
"At this stage it is very difficult to judge anything else, but we can be pretty happy.
"Mark (Webber) had a good two days to start with, and with me taking over it was about shaking off the rust and getting back into shape.
"It felt good to be out there back in the car which is working very well. I'm really happy with it."
As to whether the RB9 can land him a fourth straight title, the 25-year-old German was a little more circumspect.
"It was nice to be back in the car and not much more than that," Vettel added.
"The target is clear as to what we want to achieve this year, but there's a long way to go. We shouldn't get excited in any way.
"Now is the time to do our homework. Maybe it's not the most exciting bit of the season, but I had fun so it's not that boring."
Jenson Button, who was quickest on Tuesday in his McLaren, was down in seventh yesterday, but only because he concentrated on aero and mechanical work.
His day, however, ended five minutes early as he stopped his MP4-28 on track, apparently due to a loose wheel following a pit stop.