Fernando Alonso edged out McLaren team-mate Lewis Hamilton in the dying seconds of qualifying to take pole for Sunday's Monaco Grand Prix.
Alonso (right) beat Hamilton with his last lap of qualifying
The reigning world champion clocked one minute 15.726 seconds to pip Hamilton by less than two tenths of a second.
The Briton looked to be on his way to the first pole of his career but he got caught in traffic and lost time.
Ferrari's Felipe Massa was third but team-mate Kimi Raikkonen starts in 15th after an error saw him clip a barrier.
It is the first time McLaren have claimed a clean sweep of the front row this season as Alonso earned his first pole since the China Grand Prix last October.
"I'm very, very happy," said the Spaniard. "It was important to get the pole and it is always special in Monaco.
"We had a little bit of everything here; light rain, traffic and it was very stressful for everybody.
"Hopefully our race strategy will be better than our competitors, but it will probably be an unexpected race."
Hamilton was on course for his first career pole in Monte Carlo as he topped the time sheets in the first two periods of qualifying.
But the 22-year-old got caught up behind Red Bull's Mark Webber in the battle for pole and had to settle for second.
"I got held up by Webber who was on an out-lap and he didn't let me pass until Turn Eight so I lost half a second," explained Hamilton.
"But I had a fantastic session, it was exciting and this is my favourite track. To be second here on my first Grand Prix is great and Sunday will be interesting."
After taking successive poles in Malaysia, Bahrain and Spain, Ferrari's Massa had to be satisfied with third.
It was some consolation for the Italian team as Raikkonen clipped a barrier and came to a standstill coming out of the Rascasse corner.
Raikkonen sees his hopes fade after an error in Monaco
Ferrari's mechanics could not repair his car in time for the Finn to set a flying lap and he starts down the grid in 15th.
There was also an element of bad luck and misjudgement for Red Bull's David Coulthard, who was disqualified from the final qualifying spell after blocking Heikki Kovalainen.
Coulthard's penalty, for not letting the Renault driver overtake him, means he starts 16th on the grid.
"I wasn't trying to screw anyone's lap it was just lack of communication," said Coulthard.
"I didn't know Kovalainen was on a timed lap but if you start that far down on the grid it is going to be a long afternoon."
Coulthard's penalty handed fellow Briton Jenson Button a spot in the final shoot-out and he qualified in 10th, his best display of the season.
"I'm happy to be in the top 10," said the Honda driver. "I think it's an improvement, it really is and is very promising."
The fourth Briton in the field, Anthony Davidson, starts in 17th for Super Aguri.
Qualifying result for the Monaco Grand Prix:
1. Fernando Alonso (Spain) McLaren 1:15.726
2. Lewis Hamilton (Britain) McLaren 1:15.905
3. Felipe Massa (Brazil) Ferrari 1:15.967
4. Giancarlo Fisichella (Italy) Renault 1:16.285
5. Nico Rosberg (Germany) Williams-Toyota 1:16.439
6. Mark Webber (Australia) Red Bull-Renault 1:16.784
7. Nick Heidfeld (Germany) BMW Sauber 1:16.832
8. Robert Kubica (Poland) BMW Sauber 1:16.955
9. Rubens Barrichello (Brazil) Honda 1:17.498
10. Jenson Button (Britain) Honda 1:17.939
11. Alexander Wurz (Austria) Williams-Toyota 1:16.662
12. Vitantonio Liuzzi (Italy) Toro Rosso-Ferrari 1:16.703
13. Jarno Trulli (Italy) Toyota 1:16.988
14. Heikki Kovalainen (Finland) Renault 1:17.125
15. Kimi Raikkonen (Finland) Ferrari no time
16. David Coulthard (Britain) Red Bull-Renault * no time
17. Anthony Davidson (Britain) Super Aguri-Honda 1:18.250
18. Scott Speed (U.S.) Toro Rosso-Ferrari 1:18.390
19. Adrian Sutil (Germany) Spyker-Ferrari 1:18.418
20. Ralf Schumacher (Germany) Toyota 1:18.539
21. Takuma Sato (Japan) Super Aguri-Honda 1:18.554
22. Christijan Albers (Netherlands) Spyker-Ferrari no time
* Coulthard was penalised and not allowed to start in the third session. He was replaced by Button.