Triple world champion and current championship leader Vettel was a quarter of a second quicker than team-mate Mark Webber around the twisty Hungaroring circuit that basked in 30 degree centigrade heat, and with the track temperature hitting 44.
For Pirelli, they are ideal conditions under which to further run the rule over their new specification of tyres making their proper debut this weekend after an initial three-day run in last week's young driver test at Silverstone.
Following a series of blowdous during the British Grand Prix earlier this month, Pirelli were rapidly forced to revise their tyres, opting for a solution that comprises last year's structure with this year's compounds.
Ten of the 11 teams managed to clock up the miles last week, all bar Mercedes who were banned after conducting a private test with Pirelli in Barcelona in mid-May.
That has placed the Brackley-based marque on the backfoot coming into this event, so for Lewis Hamilton and Nico Rosberg, the opening 90 minutes today were all about gaining as much information as possible.
Both drivers clocked up a session high of 28 laps, with Rosberg down in eighth place on the timesheet, eight tenths of a second adrift of German compatriot Vettel.
As for Hamilton, the 28-year-old Briton was 13th and 1.434secs back on Vettel's lap of one minute 22.723secs.
Behind the Red Bulls were Vettel's main title rivals in Kimi Raikkonen in his Lotus and Ferrari's Fernando Alonso, both just under four tenths of a second adrift.
Trailing by 41 and 34 points respectively, both men know they have to close the gap to Vettel this weekend ahead of the looming summer shutdown that follows this event.
Romain Grosjean was fifth in his Lotus, followed by Jenson Button for McLaren, the 33-year-old Briton 0.647secs back.
With team-mate Sergio Perez ninth, a further two tenths of a second off the pace, McLaren appear to have taken a step forward, although it is too early to suggest whether they will be closer to the leaders this weekend.
Force India's Adrian Sutil, on the occasion of his 100th grand prix, was seventh, 1.2secs ahead of team-mate Paul Di Resta who was a surprisingly lowly 18th.
Marussia's Max Chilton sat on the sidelines for the session as the team's reserve Rodolfo Gonzalez took up his seat.
The Venezuelan, however, was last and 6.2secs down on Vettel, and 1.3secs adrift of team-mate Jules Bianchi.
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