Sebastian Vettel denied Pastor Maldonado a shock timesheet-topping performance in the final seconds of the third practice session for the Spanish Grand Prix at Barcelona.
Most of the hour had seen a variety of surprise underdog names taking turns on top, before reigning champions Vettel and Red Bull re-established the expecting order with the German's final lap.
It was Sauber's Sergio Perez who led the way for most of the morning, setting the quickest time of the first half hour on the harder tyres, then being swiftly usurped by first Nico Rosberg, then Jean-Eric Vergne as the Mercedes and Toro Rosso tried softs.
Once Perez was on softs too, he was swiftly back in front, lapping in 1m23.742s.
That held until the final two minutes, when his team-mate Kamui Kobayashi jumped to the top, followed by Red Bull's Mark Webber.
But before this pair could get to the pits, they were being usurped as Maldonado came through to put his Williams on top with a 1m23.336s.
The Venezuelan would not stay there, as with seconds left on the clock, Vettel edged him out by 0.168 seconds.
Maldonado, Kobayashi, Webber and Perez found themselves pushed back to second through fifth places, ahead of Ferrari's Fernando Alonso, Vergne, and fastest McLaren driver Jenson Button. The sister McLaren of Lewis Hamilton looked poised to grab first place on the Briton's soft tyre run, only to encounter heavy traffic in the middle of the chicane, leaving Hamilton an unrepresentative 16th.
Romain Grosjean did not complete any flying laps after a fuel pressure issue stranded his Lotus at Turn 10 early on, while Timo Glock was the other man to park trackside following an apparent issue at the final chicane in the closing minutes. The German stopped his Marussia just past the pit exit.
Pos Driver Team Time Laps 1. Sebastian Vettel Red Bull-Renault 1m23.168 13 2. Pastor Maldonado Williams-Renault 1m23.336s + 0.168 19 3. Kamui Kobayashi Sauber-Ferrari 1m23.350s + 0.182 19 4. Mark Webber Red Bull-Renault 1m23.578s + 0.410 16 5. Sergio Perez Sauber-Ferrari 1m23.742s + 0.574 22 6. Fernando Alonso Ferrari 1m23.807s + 0.639 15 7. Jean-Eric Vergne Toro Rosso-Ferrari 1m23.833s + 0.665 14 8. Jenson Button McLaren-Mercedes 1m23.909s + 0.741 13 9. Kimi Raikkonen Lotus-Renault 1m23.936s + 0.768 16 10. Nico Rosberg Mercedes 1m24.070s + 0.902 23 11. Felipe Massa Ferrari 1m24.179s + 1.011 16 12. Nico Hulkenberg Force India-Mercedes 1m24.323s + 1.155 17 13. Daniel Ricciardo Toro Rosso-Ferrari 1m24.331s + 1.163 15 14. Bruno Senna Williams-Renault 1m24.409s + 1.241 18 15. Paul di Resta Force India-Mercedes 1m24.599s + 1.431 15 16. Lewis Hamilton McLaren-Mercedes 1m24.778s + 1.610 15 17. Michael Schumacher Mercedes 1m24.825s + 1.657 17 18. Vitaly Petrov Caterham-Renault 1m25.911s + 2.743 20 19. Heikki Kovalainen Caterham-Renault 1m26.587s + 3.419 20 20. Charles Pic Marussia-Cosworth 1m27.469s + 4.301 18 21. Timo Glock Marussia-Cosworth 1m27.689s + 4.521 16 22. Narain Karthikeyan HRT-Cosworth 1m28.207s + 5.039 24 23. Pedro de la Rosa HRT-Cosworth 1m28.373s + 5.205 13 24. Romain Grosjean Lotus-Renault no time 2 All Timing Unofficial