Vettel strong in Brazil

Vettel led Webber in a Red Bull one-two morning and afternoon, a day after the Australian had described himself as an 'inconvenient' title contender and accused the championship-leading Formula One team of favouring the young German.

Vettel's subsequent remark, to German television, that "If Mark needs help then he should take the medical car" hardly improved relations.

Ferrari's Fernando Alonso, who leads Webber in the championship by 11 points and could clinch his third Formula One title if results go his way on Sunday, was third fastest in the afternoon after an engine problem in the morning.

However, Ferrari, who have been managing the Spaniard's engines carefully for months after early-season problems, were unconcerned and had planned anyway to change the unit before second practice.

"The situation is going on according to plans," Ferrari had said on their Twitter feed.

Alonso was 13th fastest in the morning with Brazilian team mate Felipe Massa 14th.

Red Bull, with Vettel desperate to win after engine failure while leading in South Korea left the young German 25 points behind Alonso with two races remaining, looked very much the team to beat.

Vettel's best time of one minute 11.968 seconds was 0.104 quicker than the best effort by Webber, who won last year's race at Interlagos.

The difference between the two in the first session was nearly half a second.

McLaren's Lewis Hamilton, third in the championship challenge and 21 points behind Alonso, was third and fourth respectively.

Team-mate and world champion Jenson Button, the fifth driver still in mathematical contention but 42 points off the pace on his return to the track where he won the title with Brawn last year, was fourth and seventh.

Renault's Russian rookie Vitaly Petrov spun into the tyre barriers with eight minutes of the morning session remaining while Sauber's Japanese driver Kamui Kobayashi also went off at Ferradura with a puncture.