If Hamilton wins, Alonso would then only need a top-five finish to guarantee the title.
Vettel needs to win with Alonso out of the top four to be champion.
Brazilian Piquet was asked to deliberately crash to help team-mate Fernando Alonso to win the race.
Alonso said he felt the result in Spa "didn't change anything" in the championship.
"I just told them I put in my time and I'm moving forward, " Alonso said.
Alonso has something to say about that though and immediately sets the fastest time of 1:26.841.
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"In the four years with Ferrari this is the best (car) we've had, " Alonso said.
Among those to congratulate Hamilton was former McLaren team-mate and double world champion Fernando Alonso.
Potential targets include Real Sociedad's Xavi Alonso, Valencia defender Fabian Ayala and Francesco Totti of Roma.
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Spain's Fernando Alonso has been tipped as a possible replacement for Yoong in Hungary and Belgium.
Alonso drove for Minardi last year and has secured a seat at Renault next season.
Michelle Rodriguez, Giovanni Ribisi, Joel David Moore, CCH Pounder, Wes Studi and Laz Alonso.
Only Real Madrid's Cristiano Ronaldo and Xabi Alonso make the list for the Spanish teams.
Alonso, champion in 2005 and 2006, will spearhead Ferrari's challenge following his move from Renault.
Vettel beat Ferrari's Fernando Alonso by 0.076 seconds, with the Spaniard's team-mate Felipe Massa in third.
But Alonso said he expected McLaren to be on top in qualifying on Saturday.
Ferrari were not competitive in the first session, when Alonso was 0.850secs off Button's pace.
Webber will win the title if he wins the race and Alonso is lower than second.
If Vettel wins, he needs Alonso to be lower than fourth to become champion.
Alonso made up three places in the closing stages to grab his fourth place.
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Neither have any hip hop celebrities, a moneyed buyer base Alonso initially suspected would express interest.
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He and Alonso will make a strong driver line-up, combining youth, experience, speed and flair.
Robert Kubica took second for Renault, ahead of the Ferraris of Felipe Massa and Fernando Alonso.
Alonso may have won fantastically in front of his home crowd, but he was cautious afterwards.
Mark Webber, Fernando Alonso, and Jenson Button will start in second, third and fourth position.
Grosjean's teammate Kimi Raikkonen took fifth, ahead of the two Ferrari drivers Alonso and Felipe Massa.
And Fernando Alonso got big cheers on the basis that he clearly doesn't like Hamilton.
In other words, if Vettel won, Alonso would have to finish fourth or better.
Alonso has managed to lead in points much of this season despite piloting a less-competitive car.
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Dr Alonso's previous work in Tanzania showed that immunity was conferred in 59% of them.
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