Lewis Hamilton denied Sebastian Vettel Friday honours at a grand prix for the first time since F1 returned from its summer break after sweeping the opening day of the Korean Grand Prix.

The Briton improved his FP1 benchmark to 1min 38.673secs during the course of the second 90-minute session, courtesy of running on the option Pirelli tyre, and increased his advantage over Vettel from 0.03secs to 0.108secs in the process. The Red Bull driver - who suffered a KERS scare mid-session - would not be shaken, however, and it would appear that a genuine qualifying battle may be on the cards on Saturday afternoon.

Mercedes' potential was underlined when Nico Rosberg leap-frogged Mark Webber to claim third spot, the German just 0.016secs behind countryman Vettel, with Webber only fractionally slower in fourth place. The leading quartet were the only drivers to duck under 1min 39secs, with Felipe Massa next up, four-tenths off the pace.

Both the Scuderia and Lotus got the better of McLaren in FP2, Massa, Romain Grosjean, Fernando Alonso and Kimi Raikkonen all demoting Jenson Button. The Finn showed no signs of suffering from his late off in FP1, but was the first driver a full second off Hamilton's pace.

Button and Force India's Adrian Sutil rounded out the top ten, although the German was just 0.001secs ahead of team-mate Paul di Resta, with Sergio Perez and Esteban Gutierrez not far behind. The Mexican edged Sauber team-mate Nico Hulkenberg for 13th, with the Toro Rossos of Jean-Eric Vergne and Daniel Ricciardo queuing up behind the German and ahead of the two Williams cars.

At the back, Giedo van der Garde came out on top of the Caterham-Marussia battle, out-pacing team-mate Charles Pic by three-tenths after the Frenchman joined the list of those to spin on the still dusty circuit. Jules Bianchi, who missed the first session to allow reserve Rodolfo Gonzalez a run in the lead Marussia, took the penultimate spot in the order, ahead of team-mate Max Chilton.