Fernando Alonso heads into Bahrain qualifying as the fastest driver around the Sakhir circuit, having posted a 1:54.099 in Saturday's final practice.
The Spaniard, who was already in the top four before his late charge on the softer rubber, took the honours by 0.269s over Mercedes GP driver Nico Rosberg while Mark Webber was third quickest.
The final practice session, which took place in sweltering hot conditions, saw the top seven separated by less than a second and with four teams in the mix as McLaren's Jenson Button finished P7 behind Michael Schumacher, Seb Vettel and Felipe Massa.
Report: Blue skies and a track temperature of 42'C awaited the drivers in the third and final practice session for the season-opening Bahrain GP. With just an hour to get the cars up to scratch ahead of qualifying, the drivers were quickly out on track with everyone barring the two Red Bulls and HRTs completing their installation laps within the first five minutes.
Problems already for Lucas di Grassi, who returned to his Virgin garage after his first lap reporting a gearbox problem. The two Red Bulls finally went out and both stayed out on track to set the first times with Sebastian Vettel ahead of Mark Webber with a 1:55.178.
Seb Buemi went third and Ferrari, who have downplayed claims that they are the favourites to win this weekend's race, joined the action. However, Fernando Alonso slowed down at the end of his first lap after a bumpy ride of the kerbs.
Michael Schumacher, who admitted on Friday that he needs to up his game, took second place, 0.162s behind Vettel. His team-mate Nico Rosberg slotted into third place.
Major problems for Virgin Racing, though, as Timo Glock lost an entire wheel as he turned into a lefthander. Fellow newcomer Bruno Senna had to slow down and take evasive action to avoid the tyre. Not great for Virgin and extremely dangerous.
The FIA were quick to get down to Virgin's garage and inspect the problem. Initial reports claim the problem was with a wheel nut, which was not tightened due to a faulty wheel nut gun. It remains to be seen what the FIA will have to say about this matter.
Back to the action and Felipe Massa went quickest with a 1:54.761 while his team-mate Alonso took second place. Lewis Hamilton improved to seventh place ahead of Pedro de la Rosa and Jaime Alguersuari. Rosberg moved up to second place, 0.084s behind Massa.
A fastest final sector from Jenson Button saw him climb to sixth place as he rode the kerbs and bumped his way to a 1:55.763.
Senna returned to the track as Adrian Sutil slotted into eighth only to lose it moments later to Robert Kubica. Senna finally completed a lap, 11.5s off the pace.
Schumacher returned to the track, jerking and twisting around Turn Six, which cost him valuable time - and almost rear-ending Alonso as the two entered the pits nose-to-stern.
And problems for Hamilton, who is out for the rest of the session due to an as yet undisclosed problem at the front left of his car. It is not yet know if it's brakes or what but whatever it is, it will keep the 2008 World Champion from doing a qualy sim ahead of qualifying.
Glock, back on track after his earlier tyre woes, moved up to 19th place while there was still no sign of Karun Chandhok for HRT. And if the Indian driver doesn't complete a lap in practice he won't be allowed to take part in qualifying or Sunday's race. So big problems for the 26-year-old and his team.
The final seven minutes saw the drivers put on the softer tyres to see what their cars can do. Alonso went quickest,a 1:54.099, sixth-tenths up his team-mate, Tonio Liuzzi improved to sixth, Sutil to seventh, Webber second, Schumacher third, Vettel fourth and Rosberg second.
Times
1. Alonso Ferrari 1:54.099 14 laps
2. Rosberg Mercedes 1:54.368 + 0.269 13 laps
3. Webber Red Bull-Renault 1:54.500 + 0.401 15 laps
4. Schumacher Mercedes 1:54.533 + 0.434 13 laps
5. Vettel Red Bull-Renault 1:54.646 + 0.547 16 laps
6. Massa Ferrari 1:54.739 + 0.640 14 laps
7. Button McLaren-Mercedes 1:55.000 + 0.901 14 laps
8. Kubica Renault 1:55.331 + 1.232 15 laps
9. Liuzzi Force India-Mercedes 1:55.432 + 1.333 11 laps
10. Hulkenberg Williams-Cosworth 1:55.461 + 1.362 13 laps
11. Sutil Force India-Mercedes 1:55.521 + 1.422 13 laps
12. Hamilton McLaren-Mercedes 1:55.860 + 1.761 8 laps
13. de la Rosa Sauber-Ferrari 1:56.063 + 1.964 14 laps
14. Barrichello Williams-Cosworth 1:56.259 + 2.160 15 laps
15. Buemi Toro Rosso-Ferrari 1:56.295 + 2.196 17 laps
16. Alguersuari Toro Rosso-Ferrari 1:56.504 + 2.405 16 laps
17. Kobayashi Sauber-Ferrari 1:56.530 + 2.431 13 laps
18. Petrov Renault 1:56.811 + 2.712 16 laps
19. Glock Virgin-Cosworth 1:59.173 + 5.074 10 laps
20. Kovalainen Lotus-Cosworth 1:59.789 + 5.690 15 laps
21. Trulli Lotus-Cosworth 2:01.259 + 7.160 5 laps
22. Senna HRT-Cosworth 2:04.001 + 9.902 11 laps
23. di Grassi Virgin-Cosworth 2 laps
24. Chandhok HRT-Cosworth
Source: Planet-F1