Renault's Robert Kubica served notice that he will be a serious pole threat in Monaco qualifying after setting the fastest time in final practice, just ahead of Felipe Massa (Ferrari) and Mark Webber (Red Bull). But the big news of the session was that Thursday pacesetter Fernando Alonso severely damaged his Ferrari in a crash.
The two-time champion was fastest already when 20 minutes into the session he lost control heading into Massenet and hit the barriers, removing both right-side wheels, and giving Ferrari a large amount of work to do before qualifying.
After the relative serenity of Thursday's sessions, final practice was significantly more fraught and eventful. The top spot changed hands on multiple occasions, with Toro Rosso's Jaime Alguersuari and Michael Schumacher (Mercedes) swapping first place several times early on, before Red Bull's Sebastian Vettel, Alonso, Kubica, and McLaren's Lewis Hamilton all took turns up front.
Webber then moved to the head of the field with 15 minutes to go, and looked set to go farther ahead on his late soft tire run had he not been delayed behind Schumacher – who had himself slowed to avoid being blocked by Vitaly Petrov's Renault.
It was Kubica who deposed Webber going into the final minutes, the Pole going 0.4sec clear despite having to dodge around two cars in the final corners.
Webber also improved but was not quite quick enough to beat Kubica, and the pair were then split when Massa found himself some space on his final lap and jumped to second, 0.046sec behind Kubica.
Hamilton, Vettel and Schumacher ended up in fourth through sixth positions, followed by Nico Rosberg in the second Mercedes and Toro Rosso's Sebastien Buemi.
Championship leader Jenson Button was only 10th, behind Adrian Sutil, and complained over the radio of a lack of grip.
Schumacher and Petrov were among the many drivers to have minor incidents during the hour, in their case taking separate trips down the Mirabeau escape road. Petrov also came close to running into Lucas di Grassi when caught out by how quickly the Virgin slowed for the chicane. Timo Glock missed most of the hour after the sister Virgin came to a halt in the chicane escape road with a mechanical problem.
Sutil required a new rear wing on his Force India after spinning into the Casino Square barriers, and Massa came close to damaging the second Ferrari with some lurid near-misses at Loews and the Swimming Pool exit.
Pos Driver Team Time Laps
1. Kubica Renault 1:14.806 25
2. Massa Ferrari 1:14.852 + 0.046 22
3. Webber Red Bull-Renault 1:14.945 + 0.139 24
4. Hamilton McLaren-Mercedes 1:15.038 + 0.232 24
5. Vettel Red Bull-Renault 1:15.046 + 0.240 25
6. Schumacher Mercedes 1:15.236 + 0.430 21
7. Rosberg Mercedes 1:15.252 + 0.446 20
8. Buemi Toro Rosso-Ferrari 1:15.537 + 0.731 21
9. Sutil Force India-Mercedes 1:15.659 + 0.853 13
10. Button McLaren-Mercedes 1:15.682 + 0.876 22
11. Liuzzi Force India-Mercedes 1:15.691 + 0.885 19
12. Alguersuari Toro Rosso-Ferrari 1:15.769 + 0.963 26
13. Hulkenberg Williams-Cosworth 1:16.164 + 1.358 24
14. Barrichello Williams-Cosworth 1:16.232 + 1.426 21
15. Petrov Renault 1:16.240 + 1.434 26
16. Alonso Ferrari 1:16.266 + 1.460 6
17. Kobayashi Sauber-Ferrari 1:16.644 + 1.838 25
18. de la Rosa Sauber-Ferrari 1:16.696 + 1.890 22
19. Kovalainen Lotus-Cosworth 1:17.782 + 2.976 18
20. Trulli Lotus-Cosworth 1:17.865 + 3.059 26
21. di Grassi Virgin-Cosworth 1:18.063 + 3.257 24
22. Senna HRT-Cosworth 1:19.720 + 4.914 25
23. Chandhok HRT-Cosworth 1:19.781 + 4.975 21
24. Glock Virgin-Cosworth 3
All Timing Unofficial