Championship leader Alonso: 'Ferrari must improve'

(CNN) -- Formula One world championship leader Fernando Alonso has warned his Ferrari team they must improve if he is to win the marque's first drivers' crown since 2007.

Alonso finished third at the Singapore Grand Prix, extending his lead at the top of the 2012 standings to 29 points with just six races of the season to go.

But the two-time world champion knows Ferrari cannot continue to rely on their rivals slipping up, after McLaren's Lewis Hamilton was forced to retire from a winning position on Sunday.

"In the end it went well, but we definitely can't go on like this," the Spaniard, who saw his nearest rival Sebastian Vettel of Red Bull take the checkered flag, told Ferrari's official website.

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"It can't always be the case that my closest rival retires, as has happened in the last two races and we can't think of carrying on to the end of the season with qualifying sessions like yesterday's, when our performance was almost a second off the best.

"On track we manage to make the most of what we have, making few or no mistakes, thanks to great work from the team; for that alone we deserve to be where we are in the classification."

Alonso, who qualified fifth fastest in Singapore, predicts tougher challenges ahead when the F1 season continues at similar Asian tracks.

"Probably this has been the most difficult circuit for us: we will find partially similar characteristics in Korea and Abu Dhabi, but I hope that by the time we get there, we will have found a way of improving the car.

"It was a very tough race physically, definitely the most tiring of the whole season; three hundred odd kilometers in this heat and such high humidity is very stressful."

Vettel, the world champion in each of the last two seasons, has moved into second place in the championship standings, ahead of Lotus' Kimi Raikkonen in third position.

Finland's Raikkonen was the last driver to win the championship for Ferrari with his triumph five years ago.

The next stop on F1's world tour is the Japanese Grand Prix on October 7.