If Ferrari’s Sebastian Vettel was foxing at Australian Grand Prix practice, he was very convincing.

Vettel cut a frustrated figure and claimed Mercedes were in a “league of their own” after five-time world champion Lewis Hamilton dominated both practice sessions at the Formula 1 season opener.

Experts were sceptical after Vettel could only muster the fifth fastest time in the second practice session at Albert Park as Mercedes left Ferrari in their wake.

There were suspicions that Ferrari were hiding their true pace before Saturday’s qualifying after the Italian outfit had the quickest car in recent pre-season testing in Spain.

But four-time world champion Vettel insisted he had struggled with “car feel and handling” during practice and dipped his hat to the Mercedes juggernaut led by Hamilton.

“They looked very strong and a lot stronger than they claimed before the weekend – they were in a league of their own,” he told reporters.

After topping the timesheets in Friday’s initial 90-minute practice, Hamilton backed up in the next session to go almost a second faster.

He clocked a lap of one minute 22.60 seconds ahead of Mercedes teammate Valtteri Bottas.

Hamilton looks on track to claim a record eighth overall pole and sixth straight at Albert Park on Saturday.

Vettel admitted he would need to turn things around if he were to pull off a third straight Australian Grand Prix victory on Sunday.

“It was a tricky day for us, we are not there yet where we would like to be, not in terms of lap time but more in terms of car feel and handling,” he said.

“We didn’t really get into the groove and rhythm and that is quite important around here.

“But if we can get that confidence and groove back there is a lot of time to find around here.”

The one hour qualifying session starts at 1700 AEDT.