Vettel takes pole ahead of Red Bull teammate Webber for F1's season-opening Australian GP

Reigning Formula One world champion Sebastian Vettel claimed the pole position for the season-opening Australian Grand Prix on Sunday in a unusual qualifying session held on race day.

Vettel qualified in a time of 1 minute, 27.407 seconds around the Albert Park circuit, and was joined in an all-Red Bull front row by teammate Mark Webber, who was 0.4 seconds back.

Lewis Hamilton qualified third in his first race for Mercedes, ahead of the Ferrari pair Felipe Massa and Fernando Alonso.

The second and third sessions of qualifying were rescheduled for Sunday after a series of rain delays and the onset of darkness prevented them from being held Saturday.

Sunday's sessions were held on a track damp from morning rain. In the second session, intermediate tires were used — except for McLaren's Sergio Perez, who took an unsuccessful gamble on slicks — but the drying conditions meant the flying laps in final qualifying were all on the softer slick tires.

Vettel claimed the 37th pole of his career, and his third in four years at Albert Park.

"It definitely wasn't easy in those conditions," Vettel said. "On the dries (tires) I got in the groove and the car felt in balance."

Under the F1 rules, the top 10 drivers must start with the tires they finished qualifying on, meaning early pit stops will be required as the super-soft slicks are unlikely to last more than a handful of laps.

"It could be a couple of laps or a couple of laps more," Vettel said.

Mercedes' Nico Rosberg — who topped the time sheets in the first and second qualifying sessions — qualified in sixth, ahead of the Lotus pair Kimi Raikkonen and Romain Grosjean, followed by Paul di Resta of Force India and McLaren's Jenson Button.

Qualifying on Sunday is unusual but not unprecedented, with the grids for both the 2004 and 2010 Japanese Grands Prix decided on race day due to bad weather on Saturday.

While fans were left disappointed by the postponement, teams and drivers were unanimous in their support to delay qualifying as the conditions on the bumpy street circuit were too dangerous, with standing water on the circuit and poor lighting.

Both qualifying and the race start at 5 p.m. local time to suit European television audiences, and there are no lights on the temporary circuit.