Twice world champion Fernando Alonso said he was in the hunt for pole position at the Australian Grand Prix on Saturday before a hydraulics failure saw him crash his Alpine in the final phase of qualifying.

Spaniard Alonso was showing impressive pace before the problem shut his car down and had him plough into a wall before he could complete his lap at Albert Park.

Ferrari's Charles Leclerc ended up taking pole ahead of the Red Bull cars, while Alonso's misfortune will see him start 10th on the grid on Sunday.

"The gearbox was not working anymore,” Alonso said in the Albert Park paddock.

"The engine also switched off, power steering switched off. So I think there is something that we need to investigate when the car is back.

READ | Leclerc on pole for Australian Grand Prix

"It is unbelievable how unlucky we are, because 20 seconds later, maybe we were on pole if the car stops in turn one, instead of turn 11. These races are difficult to explain."

Despite the crash, Alonso, who won back-to-back titles in 2005 and 2006, said he had been enjoying his best race weekend in years.

"I think the car is getting better and better,” said the 40-year-old, who returned to Formula One last season after a two-year hiatus.

“We feel more confident. The team is working hard.

"Maybe (it was) a surprise to fight for pole but not a surprise to be closer and closer to the leaders.

"It has been the best weekend for years for me, and it is so frustrating not to execute it at the end."