SHANGHAI, Oct 6, 2007 (AFP) - Fernando Alonso admitted he was surprised and disappointed on Saturday after only qualifying fourth as rival Lewis Hamilton took pole in Shanghai for Sunday´s Chinese Grand Prix.

Spain´s double world champion had been quicker than his McLaren-Mercedes team-mate in the first two qualifying sessions but then saw the rookie claim his sixth pole of the season.

Hamilton leads Alonso by 12 points and can become the youngest champion and the first driver to win the championship at his first attempt with victory in the race.

Alonso, 26, who is expected to quit McLaren at the end of a controversial season, said: "I was really frustrated because I am fighting for the world championship and I am fourth.

"It is going to be really difficult for me now as I have to get ahead of three people," added Alonso, who will have the Ferraris of Kimi Raikkonen and Felipe Massa ahead of him.

He said: "I have no idea where I lost the half-a-second. I was looking quite good in Q1 and Q2 then lost it in Q3.

"When I crossed the line I was very happy with the lap and on the radio they told me I was fourth and I was surprised because I thought I was nearly at the maximum.

"I went out on softer tyres next and improved by two-tenths and I knew it was an extremely good lap. I said on the radio this is a good lap´ and I expected to be fighting for pole then I realised I was still fourth with an even bigger gap to pole."

Alonso must finish ahead of Hamilton to keep his championship hopes alive and thus he would welcome the expected torrential rain turning the race into something of a lottery.

"We expect some rain tomorrow and we know what can happen in wet races, so fingers crossed for tomorrow for some rain and maybe I have a chance," Alonso added.