By Ian Ransom
MELBOURNE (Reuters) - Sebastian Vettel's pre-race declaration that Ferrari had a car to challenge Mercedes' dominance went untested on Friday as the four-times world champion was repeatedly thwarted by rain during practice at the season-opening Australian Grand Prix.
Reigning champion Lewis Hamilton topped the timesheets in both blustery sessions at Albert Park but Vettel could find no adequate break in the rain to make any impression.
The German was first out of the garage in the opening session but was unable to post a lap time due to the inclement weather.
Confined to wet-weather tyres in the second session, Vettel recorded the eighth-fastest time.
His team mate and fellow former world champion Kimi Raikkonen was third fastest in the second session after clocking a slow lap and taking a spin in the first.
Both completed just a single run of seven laps during free practice two.
Hamilton remarked that he felt Ferrari had something "up their sleeve" in Melbourne, but Vettel denied he had anything to hide.
“I was trying (to post a time) but every time I got out it started to rain,” he said in the paddock at Albert Park.
“I think there were a lot of people that were struggling today with the conditions.
“Sometimes it's like this,” he added. “It was supposed to rain all day, it didn't but it was raining every now and then which was enough to wet parts of the track. There was not much we could learn today.
"It was not ideal but in the end what can you do? It's the same for everyone. It was good to get some laps at least to feel the car."
(Editing by Nick Mulvenney)