Lewis Hamilton's bid for a practice clean sweep for the first time in his Formula One career fell just short on Saturday in the final session ahead of qualifying for the Canadian Grand Prix.
Hamilton topped the timesheet at the end of Friday's two 90-minute runs and, with 15 minutes remaining in the hour-long outing today at the Circuit Gilles Villeneuve, again led the way.
Hamilton, however, had to settle for third come the conclusion, primarily as he failed to find a clean run after emerging on the supersoft tyres for a quick blast in the closing stages.
Instead it was reigning champion Sebastian Vettel who was fastest in his Red Bull by just six thousandths of a second from Ferrari's Fernando Alonso, the current championship leader.
The 24-year-old German posted a lap of one minute 14.442 seconds, aided by the conditions as blue skies dominated over Montreal, and with temperatures hitting 22 degrees and due to rise for qualifying.
Baulked on his supersoft tyre laps, Hamilton finished 0.270secs off Vettel, followed closely by Red Bull's Mark Webber, Williams' Pastor Maldonado, Ferrari's Felipe Massa and Michael Schumacher in his Mercedes, the quintet covered by just 0.084s.
The top 16 in total, down to Toro Rosso's Daniel Ricciardo, were split by a second as the session proved to be one of the most competitive of the year.
After a worrying day yesterday, the Lotus pair of Romain Grosjean and Kimi Raikkonen managed to force their way into the top 10, with Force India's Nico Hulkenberg 10th, 0.550 down.
The German had team-mate Paul Di Resta directly behind him, the Scot a further 0.075 down, whilst Jenson Button could only manage 15th in his McLaren, 0.885 off Vettel.
Button endured a frustrating day yesterday, managing precious little running due to an oil leak which required the gearbox to be changed on two occasions.
The speed is clearly in the car, as Hamilton is proving, but the 32-year-old faces another fight to make it into the top 10 based on his speed and performance so far.
At the bottom of the timesheet were Jean-Eric Vergne in his Toro Rosso and Mercedes' Nico Rosberg.
Vergne managed 17 minutes, but on his fourth installation lap the Frenchman managed to catch a patch of grass which was enough to send him sliding into a barrier at turn one.
As for Rosberg, his session was over with less than five minutes elapsed, the German pulling his car over at the left-hander turn seven after suffering what appeared to be a mechanical issue.
Times
01 Sebastian Vettel Red Bull 1:14.442 22 laps
02 Fernando Alonso Ferrari 1:14.448 0.006 17 laps
03 Lewis Hamilton McLaren 1:14.712 0.270 19 laps
04 Mark Webber Red Bull 1:14.724 0.282 21 laps
05 Pastor Maldonado Williams 1:14.755 0.313 22 laps
06 Felipe Massa Ferrari 1:14.767 0.325 21 laps
07 Michael Schumacher Mercedes 1:14.796 0.354 19 laps
08 Romain Grosjean Lotus 1:14.873 0.431 20 laps
09 Kimi Raikkonen Lotus 1:14.977 0.535 21 laps
10 Nico Hulkenberg Force India 1:14.992 0.550 22 laps
11 Paul di Resta Force India 1:15.067 0.625 19 laps
12 Sergio Perez Sauber 1:15.112 0.670 21 laps
13 Kamui Kobayashi Sauber 1:15.126 0.684 24 laps
14 Bruno Senna Williams 1:15.237 0.795 22 laps
15 Jenson Button McLaren 1:15.327 0.885 22 laps
16 Daniel Ricciardo Toro Rosso 1:15.498 1.056 19 laps
17 Vitaly Petrov Caterham 1:16.268 1.826 24 laps
18 Heikki Kovalainen Caterham 1:16.545 2.103 20 laps
19 Pedro de la Rosa HRT 1:17.705 3.263 21 laps
20 Timo Glock Marussia 1:17.974 3.532 23 laps
21 Narain Karthikeyan HRT 1:18.189 3.747 21 laps
22 Charles Pic Marussia 1:18.684 4.242 23 laps
Nico Rosberg Mercedes 1 lap
Jean-Eric Vergne Toro Rosso 3 laps
