Mark Webber remained fastest in the second free practice session for the Malaysian Grand Prix as Red Bull continued to look the class of the field in Sepang, but this time the team was run closer by Jenson Button's McLaren.
The top four drivers were covered by less than 0.250s, as Webber's 1m36.876s - on Pirelli's Option - proved to be the quickest lap of the day, set just after halfway through the 90 minutes and in response to Sebastian Vettel's 1m37.090s.
The two Red Bulls were split, however, with Button and Lewis Hamilton going second and third fastest.
Michael Schumacher survived a scary grassy moment down at Turn 6 to go fifth fastest for Mercedes ahead of Felipe Massa's Ferrari.
Nico Rosberg was seventh ahead of Nick Heidfeld, who recovered some of this morning's lost time to go eighth fastest with Fernando Alonso and Jaime Alguersuari completing the top ten.
The session was fairly uneventful, with the exception of a crash for Pastor Maldonado, who got his right tyres on the grass on the pit entry and dumped his Williams in the barrier. It was a shame for the Venezuelan, who looked fast for much of the day.
He did however end up just faster than team-mate Ruben Barrichello, as the pair occupied 11th and 12th.
The last 30 minutes did highlight some interesting tyre degradation rates as the teams switched to high fuel and soft tyres. Some eight seconds slower than the ultimate pace, most ran in the mid-1m44s bracket. But Webber fired an ominous warning shot with his final 1m43s lap late on in race trim.
Vitantonio Liuzzi caused the only other notable yellow flag when ran wide over some kerbing which appeared to switch off his HRT's Cosworth engine.
Despite this the Italian managed to outpace Heikki Kovalainen's Lotus to go 22nd, the Finn having spent most of the second session in the pits.
Pos Driver Team Time Laps
1. Mark Webber Red Bull-Renault 1m36.876s 24
2. Jenson Button McLaren-Mercedes 1m36.881s + 0.005 30
3. Lewis Hamilton McLaren-Mercedes 1m37.010s + 0.134 23
4. Sebastian Vettel Red Bull-Renault 1m37.090s + 0.214 30
5. Michael Schumacher Mercedes 1m38.088s + 1.212 26
6. Felipe Massa Ferrari 1m38.089s + 1.213 31
7. Nico Rosberg Mercedes 1m38.565s + 1.689 25
8. Nick Heidfeld Renault 1m38.570s + 1.694 16
9. Fernando Alonso Ferrari 1m38.583s + 1.707 27
10. Jaime Alguersuari Toro Rosso-Ferrari 1m38.846s + 1.970 31
11. Pastor Maldonado Williams-Cosworth 1m38.968s + 2.092 25
12. Rubens Barrichello Williams-Cosworth 1m39.187s + 2.311 30
13. Vitaly Petrov Renault 1m39.267s + 2.391 17
14. Kamui Kobayashi Sauber-Ferrari 1m39.398s + 2.522 29
15. Sergio Perez Sauber-Ferrari 1m39.603s + 2.727 34
16. Paul di Resta Force India-Mercedes 1m39.625s + 2.749 31
17. Adrian Sutil Force India-Mercedes 1m39.809s + 2.933 28
18. Sebastien Buemi Toro Rosso-Ferrari 1m40.115s + 3.239 31
19. Timo Glock Virgin-Cosworth 1m40.866s + 3.990 24
20. Jarno Trulli Lotus-Renault 1m41.890s + 5.014 19
21. Narain Karthikeyan HRT-Cosworth 1m43.197s + 6.321 15
22. Tonio Liuzzi HRT-Cosworth 1m43.991s + 7.115 14
23. Heikki Kovalainen Lotus-Renault 1m44.886s + 8.010 4
All Timing Unofficial