Newly-crowned four-times World champion Sebastian Vettel showed no signs of easing up as he led a Red Bull one-two in free practice for the Abu Dhabi Formula One Grand Prix on Friday.The 26-year-old German, who secured his fourth successive title at the 2013 Indian GP, scorched around the Yas Marina circuit with a best time of 1min41.335 seconds in the evening session. Australian team mate Mark Webber was 0.155 slower.STILL FIGHTINGLotus's Romain Grosjean, whose team mate Kimi Raikkonen won 2012's race, was fastest in the searing heat of the afternoon in 1min44.241 but had a front brake failure under the floodlights.Force India's Paul Di Resta and McLaren's Jenson Button both suffered punctures.Lewis Hamilton, winner in 2011 and twice on pole at the circuit, was second quickest for Mercedes in the opening session, just 0.192 slower than Grosjean, and third in the evening.Raikkonen, who triggered speculation about his relationship with the team when he failed to appear for Thursday's media activities at the circuit, finally turned up and was sixth and fourth fastest respectively in the two sessions.Grosjean has beaten Raikkonen in the last two races and finished on the podium in the last three.Vettel, the sport's youngest quadruple champion, is chasing his seventh successive race victory to equal fellow-German Michael Schumacher's 2004 streak. That is the longest winning run of the modern era, with the record of nine set by Italian Alberto Ascari over the 1952 and 1953 seasons.Red Bull has already clinched their fourth successive Constructors' title and the focus is now on whether anyone can stop Red Bull and Vettel winning the last three races of 2013.Vettel has won two of the four races held in Abu Dhabi, including 2010 when he clinched his first championship.Webber was fourth quickest before the sun set and the floodlights came on, with Nico Rosberg fifth for Mercedes in both sessions.Ferrari's Fernando Alonso, who had been the only man mathematically capable of making Vettel wait for the title in India, was 12th and eighth with Brazilian team mate Felipe Massa 17th and 10th. 2nd Free Practice Session from the Formula 1 Abu Dhabi Grand Prix at Yas Marina Circuit1. Sebastian Vettel (Germany) RedBull - Renault 1:41.335 2. Mark Webber (Australia) RedBull - Renault 1:41.490 3. Lewis Hamilton (Britain) Mercedes 1:41.690 4. Kimi Raikkonen (Finland) Lotus - Renault 1:41.726 5. Nico Rosberg (Germany) Mercedes 1:41.758 6. Sergio Perez (Mexico) McLaren 1:42.006 7. Jenson Button (Britain) McLaren 1:42.010 8. Fernando Alonso (Spain) Ferrari 1:42.171 9. Nico Huelkenberg (Germany) Sauber - Ferrari 1:42.324 10. Felipe Massa (Brazil) Ferrari 1:42.440 11. Esteban Gutierrez (Mexico) Sauber - Ferrari 1:42.509 12. Romain Grosjean (France) Lotus - Renault 1:42.607 13. Paul Di Resta (Britain) Force India - Mercedes 1:42.806 14. Pastor Maldonado (Venezuela) Williams - Renault 1:42.952 15. Adrian Sutil (Germany) Force India - Mercedes 1:42.998 16. Daniel Ricciardo (Australia) Toro Rosso - Ferrari 1:43.152 17. Jean-Eric Vergne (France) Toro Rosso - Ferrari 1:43.271 18. Valtteri Bottas (Finland) Williams - Renault 1:43.565 19. Giedo van der Garde (Netherlands) Caterham - Renault 1:44.138 20. Jules Bianchi (France) Marussia - Cosworth 1:44.459 21. Charles Pic (France) Caterham - Renault 1:44.525 22. Max Chilton (Britain) Marussia - Cosworth 1:45.565 Stay with Wheels24 for the 2013 Abu Dhabi weekend.