Sebastian Vettel gave his Red Bull team a surprise first pole position ahead of Renault's Fernando Alonso in qualifying for the Chinese Grand Prix on Saturday. The 21-year-old German grabbed the second pole position of his Formula One career with a last-gasp lap of one minute 36.184 seconds. With Red Bull teammate Mark Webber third behind Alonso, the previously dominant Brawn GP cars of Rubens Barrichello and Jenson Button were pegged back in fourth and fifth. “Unbelievable that we made it to pole,” said Vettel, who became Formula One's youngest race winner in Italy with Toro Rosso last year. “It was not easy. We had some problems with the car and we tried to run as little laps as possible.” Spaniard Alonso, who clocked 1.36.381, was an equally surprising presence in second for Renault, who made some radical changes to their car as they scrambled to catch up with the teams using the controversial rear diffusers. “It has been strange for us with a completely new car, we went in to qualifying with some doubts and we are very happy with the result for sure,” said the twice former world champion. Australian Webber's time of 1.36.466 was enough to beat the Brawn of Barrichello in fourth with the Brazilian's British teammate Button, who won the first two races of the season from pole, in fifth. Post-qualifying car weights released by the governing body showed Alonso would start with the lightest car on the grid, 24kg lighter than Barrichello, while Brawn had clearly gone for race pace. “We knew they were competitive but we didn't think they were quite that competitive,” championship leader Button, whose car was revealed to be 15kg heavier than Vettel's, said of the Red Bull duo. “It's a pity that we are starting behind them because its very tough here to overtake. So we'll see what happens.” Toyota's Jarno Trulli and Nico Rosberg of Williams, both using the diffuser that was declared legal at an appeal hearing earlier in the week, were sixth and seventh ahead of the last two world champions, Kimi Raikkonen of Ferrari and Lewis Hamilton in the McLaren. Although Ferrari continues to struggle with Felipe Massa missing out on the last round of qualifying and languishing in 13th place, defending champion Hamilton saw promise in his ninth place. Trulli's teammate Timo Glock missed out on the top 10, having had his gearbox replaced, and the German will be relegated from 14th to 19th on the grid for Sunday's race.