|Vettel is chasing his third consecutive win of the season this weekend [AFP]
Red Bull's successful start to the Formula One season continued as champion Sebastian Vettel dominated practice sessions ahead of the weekend's Chinese Grand Prix.
Vettel's best time was almost two tenths of a second faster than McLaren's Lewis Hamilton, who in turn was a tenth faster than teammate Jenson Button in an afternoon practice session that was shrouded in Shanghai smog.
Australian team mate Mark Webber had been second fastest in the morning but was only 10th after the break.
Vettel's strong practice performance only added to the sense of inevitability about a victory for the German this weekend. In both the opening two Grands Prix, he won the race after setting pole position, and had also claimed pole in the past two races in China.
Should he go on with the job on Saturday and Sunday, he will become the first man since Michael Schumacher in 2004 to win the opening three races of a season.
Vettel, who took Red Bull's first win as a constructor in China in 2009, said: "We found a good rhythm and we're happy with the car.
"There's still a lot to do and I think it will be tight tomorrow and on Sunday, so we'll look where we can improve.
"Today we had no big issues, but it's only Friday and so it's early in the race weekend."
Hamilton, who hinted that he could leave McLaren in search of more success if the British team cannot provide him with a car capable of winning multiple world championships, said the Red Bulls were again in firm charge.
"I've been really struggling with the balance of my car, and I don't know if that's because of the upgrade that we have, or whether it's with the set-up," the 26-year-old said.
"In the end I was able to get a relatively decent lap time, but I wasn't very comfortable in the car."
"My feeling is that they're very, very quick this weekend," Hamilton said of the Red Bulls.
"You need quite good downforce on this circuit, and they've shown time and time again that they have a little bit more than us.
"It looks like we're just behind them, but there's a little bit of a gap between us and them. They'll still be setting the pace."
After disappointing results in the opening two races of the season, Webber again struggled to keep up with Vettel's searing pace.
He was once more struck with reliability problems after his Kinetic Energy Recovery System (KERS) failed to work at all in last Sunday's Malaysian Grand Prix.
Webber said: "Generally, it was a good Friday (but) I didn't have the best P2 (second practice), particularly on the short run with the new tyres, which is why my time is down a little.
"The long run on the option tyre was good. We'll look at KERS tonight - we'd like to run it this weekend."
Webber sits in fourth place in the championship race, 28 points behind his teammate after the opening two races. Hamilton's teammate Jenson Button is second overall, followed by Hamilton in third.
Ferrari's Felipe Massa clocked the sixth best time, and Force India's Adrian Sutil was seventh ahead of the Renault pair of Nick Heidfeld - who spun into fences in both practice sessions to reduce his practice time - and
Ferrari's Fernando Alonso was 14th fastest after missing much of the afternoon with a hydraulic problem, and when he returned, he again had to do without the adjustable rear wing - a problem that also struck at Sepang.