Sebastian Vettel was second fastest to Mercedes’s Lewis Hamilton in second practice for the Korean Grand Prix as the Red Bull driver laughed off suggestions that his dominance is being achieved by illegal means. Vettel was just over a tenth of a second behind Hamilton, with the other Mercedes of Nico Rosberg third and teammate Mark Webber in fourth.

The man on course for a fourth successive drivers’ title was hit by the accusation from former team principal Giancarlo Minardi that Vettel’s car sounded like it was employing outlawed traction control in order to pull away at more than two seconds a lap from his rivals in winning the Singapore Grand Prix. The claim have been brushed off by Red Bull, while the likes of Fernando Alonso have also come out in his support. And Vettel had a joke about the suggestion after Friday afternoon’s practice.

"Overall a pretty solid day, we had no issues with the car, and there is room for improvement -- especially once we turn on the Traction Control," he told Sky Sports News.

Vettel has a massive 60 point lead over his nearest challenger Alonso as he looks to win a fourth Grand Prix on the spin this weekend in Yeongam. In addition to question marks over the legality of his performance, Vettel also faced being booed by fans while on the podium in Singapore. While he has received wide-spread support from colleagues in that regard, his suggestions that other teams were sleeping on the job to allow Red Bull to dominate has not been met favorably by Rosberg and McLaren’s Jenson Button.

An eventful weekend in Korea could be in store. Hamilton, now effectively out of the running for the title, was none the less encouraged by his showing on Friday. After several times enjoying a disappointing opening day only to rebound strongly in qualifying, he is happy that things clicked from the start this time.

“I was very happy with how the sessions went today and it's the first time I can remember that second practice has really gone well for me,” he said, according to the official Formula One website. “We haven't changed anything but the day just went smoothly and all the processes with the team worked well.”

Alonso was only seventh quickest, behind Lotus’ Romain Grosjean and teammate Felipe Massa in fifth. His new Ferrari colleague for next season, Kimi Raikkonen was eighth, ahead of Button. The Spaniard is not optimistic of an improved performance this weekend that would enable him to eat into Vettel’s advantage in the drivers’ standings.

“I am not expecting too many surprises when compared to the last few Grands Prix,” he said. “The time sheet follows the order that continues to be more or less the same seen in previous weekends and there is every probability that, again here, we can expect to struggle in the race.”

Where to watch: Qualifying for the Formula One Korean Grand Prix is scheduled to get underway at 1 a.m. ET. Coverage will be provided by the NBC Sports Network, with a live stream available on NBC Sports Live Extra.