Williams were suspended from the Formula One Teams Association on Wednesday for entering the 2010 championship and breaking what had been a united front in a standoff with the governing body. The former champions are the only current team to have formally submitted an entry, with champions Ferrari and others threatening to leave the sport unless the 2010 rules are rewritten.
Vettel came out on top, giving Ferrari their first pole position since 2012 with a masterful lap around the floodlit Singaporean track.
World champion Michael Schumacher qualified fifth fastest for Sunday's Monaco Formula One Grand Prix.
Valtteri Bottas has denied signing a pre-contract with Ferrari, saying he was amused by some of the speculation about his Formula One future.
Max Verstappen put Red Bull on pole position for his home Dutch Grand Prix at Zandvoort for the third year in a row
But BMW motorsport director Mario Theissen dismissed the comments, saying the driver himself was to blame.
Ralf Schumacher won the French GP as his team celebrated their second one-two finish in the space of a week.
Lando Norris capitalised on a bit of good fortune to win the Miami Grand Prix on Sunday
Williams claimed a first on Wednesday by revealing their 2015 car before any of their Formula One rivals had taken the wraps off theirs.
Sebastian Vettel led a Ferrari one-two at the top of the timesheets in final practice for the Bahrain Grand Prix on Saturday, ending the stranglehold of previously dominant champions Mercedes. Vettel lapped the Sakhir Circuit in a best time of one minute 31.683 seconds, 0.040 faster than team mate Kimi Raikkonen on the supersoft tyres. It was the first time this season that any driver from outside the Mercedes pairing of Nico Rosberg and triple world champion Lewis Hamilton had ended practice on top. Hamilton was quickest in all three sessions in Australia two weeks ago while championship frontrunner Rosberg led his team mate in Bahrain practices one and two on Friday. Rosberg was third fastest in practice three, his time of 1:32.104 slower than Friday when he did 1:31.001, with Hamilton fourth.
Fernando Alonso on Thursday refused to categorically rule out leaving current team Ferrari as soon as next season for either former outfit McLaren or reigning champions Red Bull.
Max Verstappen became the first Formula One driver to take 16 victories in a season
Formula One championship leader Sebastian Vettel pumped in a stunning late lap to snatch pole position from team mate Kimi Raikkonen as Ferrari dominated Chinese Grand Prix qualifying on Saturday.
The Indian driver says he would like to take the place of Williams test driver Alex Wurz's, who has been promoted as one of the team's two race drivers.
The Indian finished\nsecond in private testing for the Williams Formula One team at the Jerez circuit in Madrid.
Lewis Hamilton led a Mercedes 1-2 at the top of the timesheets for the first free practice session at the season-opening Australian Grand Prix on Friday, while McLaren's hopes of a clean start were tempered by reliability issues.
Formula One drivers expressed shock after the sport's governing body quadrupled the amount stewards can fine them to a maximum of one million euros ($1.06 million).
Ferrari felt the pain on Sunday after emerging with just two points from a hard day in front of their home fans at the Italian Grand Prix.
Red Bull's Max Verstappen started the season with a commanding Bahrain Grand Prix win from pole position.
Max Verstappen took his fifth pole position in a row at the British Grand Prix.
Seven times world champion Lewis Hamilton was seventh for Mercedes and Lance Stroll collected the final point for Aston Martin.
Max Verstappen won Red Bull's home Austrian Grand Prix from pole position and with the fastest lap on Sunday for the team's 10th successive Formula One victory and ninth in nine races this season.
Ferrari's Charles Leclerc qualified fourth with Mexican Sergio Perez, Verstappen's closest title rival and team mate but a massive 151 points adrift after 15 of 22 rounds, fifth and 0.773 off his team mate's pace.
Fernando Alonso indicated his Formula One future was in his own hands despite Red Bull announcing on Saturday that four time world champion Sebastian Vettel was leaving to join Ferrari.
Luca di Montezemolo's resignation as Ferrari chairman on Wednesday severs an historic link with the company's late founder Enzo and marks the end of an era for Formula One's most successful and glamorous team.
Max Verstappen took pole position on Saturday in a wet qualifying for a Canadian Grand Prix
Verstappen struggled for grip through qualifying but it all came together in his last effort
Max Verstappen took the 50th win of his Formula One career, and record-equalling 15th of the season
Finnish team mate Kimi Raikkonen, who started on pole for the first time in nine years but lost the lead in the pitstops, made sure of a Ferrari one-two with Hamilton finishing seventh for Mercedes after starting 13th.
Carlos Sainz put Ferrari on pole position for the US Formula One Grand Prix in Austin, Texas, on Saturday, with Red Bull's double World champion Max Verstappen joining the Spaniard on the front row.
Formula One leader Max Verstappen celebrated a record-equalling ninth successive victory on Sunday after beating the rain to win a chaotic and red-flagged Dutch Grand Prix for the third year in a row.
Max Verstappen added his name to the list of triple Formula One World champions on Saturday after Red Bull team mate and sole title rival Sergio Perez crashed out of the Qatar Grand Prix sprint race.
Ferrari's Sebastian Vettel, McLaren's Fernando Alonso and Williams' Valtteri Bottas have all been highlighted in media speculation but 22-year-old German reserve driver Pascal Wehrlein remains the bookmakers' favourite.
Max Verstappen led a soggy Monaco Grand Prix from start to finish on Sunday
Formula One is due to go through a major technical overhaul next season, with wider wheels and chassis, and a more aggressive look with revised aerodynamics aimed at making the cars faster and harder to drive.
IMAGES from the Belgian F1 Grand Prix
Max Verstappen won the Miami Grand Prix from ninth on the starting grid with a masterful display of tyre management on Sunday.
Max Verstappen leads Red Bull front row sweep in Bahrain
Max Verstappen clinched his second win of the season as the Australian Grand Prix was halted with three red flags.