http://www.bbc.co.uk/sport/0/formula1/20097576
So what you reckon? Do you think the Ferrari is fastest over a race or the RB?
Ferrari have brought several new parts to this race as they seek to stem Red Bull's advance, including a modified front wing, brake ducts, rear wing and a revised diffuser.
Alonso lost the lead of the championship to Vettel at the last race in Korea, which was the Red Bull driver's third win in a row.
On the race-simulation runs later in the session, the Red Bulls and Alonso looked evenly matched.
Vettel set the fastest lap in race trim but it came after a slow lap that would have allowed the tyres to recover.
Alonso's fastest race-simulation lap was more than 0.3 secs slower but he had not given the tyres a rest beforehand.
The fastest race-run overall was Alonso's - his average lap time was 0.2 secs quicker than Vettel's, with Lotus's Kimi Raikkonen third fastest on average followed by Hamilton. But it is difficult to know how much to read into the times as the teams do not reveal their fuel loads.
So what you reckon? Do you think the Ferrari is fastest over a race or the RB?