Jenson Button has sprung a major surprise by taking pole position for the Canadian Grand Prix, with Michael Schumacher's Ferrari in second place.
CANADIAN GP QUALIFYING
1 J Button (BAR)
2 M Schumacher (Ferrari)
3 F Alonso (Renault)
4 G Fisichella (Renault)
5 J Montoya (McLaren)
6 T Sato (BAR)
7 K Raikkonen (McLaren)
8 J Villeneuve (Sauber)
The Englishman helped bury memories of a disastrous weekend at the European GP to clock one minute 15.217 seconds.
Schumacher was 0.258secs adrift, with Renault pair Fernando Alonso and Giancarlo Fisichella third and fourth.
Juan Pablo Montoya took fifth ahead of BAR's Takuma Sato, with Kimi Raikkonen down in seventh in the other McLaren.
Raikkonen, who narrowly missed out on victory at the Nurburgring two weeks ago after a dramatic suspension failure, had been expected to challenge strongly for a fourth pole in five races.
But the Finn will start on the fourth row alongside Jacques Villeneuve, who did unexpectedly well on his home circuit to take eighth place for Sauber.
Toyota drivers Jarno Trulli and Ralf Schumacher completed the top 10, with Williams pair Nick Heidfeld and Mark Webber a disappointing 13th and 14th respectively.
It will only become clear during the race how much fuel strategy affected the grid positions.
Drivers are not allowed to refuel between qualifying and the race. That means teams who have chosen to make a later first pit stop in search of a better race strategy are penalised in qualifying because their car is heavier.
But Button's pole is a massive boost both for the driver and the team after their miserable start to the season.
Button was stripped of his points for finishing third at the San Marino Grand Prix at Imola in April after BAR were found guilty of running his car underweight.
Sato also lost his points for fifth place and the team was handed a two-race ban.
They struggled on their return at the Nurburgring as Button finished 10th and Sato 12th.
"I'm a little bit surprised actually," said Button.
"We expected to come here and be reasonably quick, but we didn't expect to challenge the Renaults and McLarens.
"It's good to be here. It's a big boost for the team. We've had a tough few months and they have worked very hard, so it's good to give them something back."
Alonso said: "It's hard to know the fuel loads of other people but we are quite happy with our strategy.
"We have one BAR and one Ferrari in front of us. That is maybe not disappointing but a surprise for sure.
"I think that in the race conditions they (McLaren) will be really, really strong."
Schumacher's second place was also a surprise after the world champion, who has won seven times in Canada, could only manage eighth fastest in Saturday practice.
But it was not all good news for Ferrari as Rubens Barrichello failed to record a time after returning to the pits with gearbox problems.
Follow the Canadian Grand Prix live on the BBC Sport website. The race starts at 1800 BST on Sunday.
Canadian GP qualifying positions:
1 J Button (BAR) one minute 15.217 seconds
2 M Schumacher (Ferrari) 1:15.475
3 F Alonso (Renault) 1:15.561
4 G Fisichella (Renault) 1:15.577
5 J Montoya (McLaren) 1:15.669
6 T Sato (BAR) 1:15.729
7 K Raikkonen (McLaren) 1:15.923
8 J Villeneuve (Sauber) 1:16.116
9 J Trulli (Toyota) 1:16.201
10 R Schumacher (Toyota) 1:16.362
11 F Massa (Sauber) 1:16.661
12 D Coulthard (Red Bull) 1:16.890
13 N Heidfeld (Williams) 1:17.081
14 M Webber (Williams) 1:17.749
15 C Albers (Minardi) 1:18.214
16 C Klien (Red Bull) 1:18.249
17 N Karthikeyan (Jordan) 1:18.664
18 T Monteiro (Jordan) 1:19.034
19 P Friesacher (Minardi) 1:19.574
20 R Barrichello (Ferrari) no time