Kimi Raikkonen finished quickest of all in what proved to be a dramatic end to an otherwise boring FP3 for the Malaysian Grand Prix.
Ferrari, Red Bull and Mercedes – albeit briefly – fought it out at the top of the timesheets a hot final practice for the Malaysian GP.
The track temperature was 44'C at the start of the hour but when the final laps were put in, it had climbed to a sweltering 51'C.
Raikkonen was quickest of all with a 1:31.880, which put him 0.162s up on Sebastian Vettel who declared it "horrible."
However, it got even worse for the German.
With five minutes of play remaining in the session he was seen touring extremely slow back to the Ferrari garage with what looked to be an engine issue.
Daniel Ricciardo was third for Red Bull, 0.211s down, while Valtteri Bottas and Lewis Hamilton were next in line.
Bottas stuck with Mercedes' new aero package for final package while Hamilton reverted to the old package. Bottas was two-tenths up on his team-mate.
Max Verstappen was sixth quickest but had a dramatic end to the session as he clashed with Jolyon Palmer. Palmer went in hot, and although Verstappen seemed to see him, he turned in on the Renault.
Palmer lost parts of his front wing, Verstappen suffered a puncture. They can expect to see the stewards later.
Sergio Perez, Felipe Massa, Esteban Ocon and Stoffel Vandoorne completed the top ten.
Pierre Gasly was P16.
1 Kimi Raikkonen Ferrari 1:31.880
2 Sebastian Vettel Ferrari 1:32.042 0.162
3 Daniel Ricciardo Red Bull 1:32.091 0.211
4 Valtteri Bottas Mercedes 1:32.329 0.449
5 Lewis Hamilton Mercedes 1:32.539 0.659
6 Max Verstappen Red Bull 1:32.579 0.699
7 Sergio Perez Force India 1:33.209 1.329
8 Felipe Massa Williams 1:33.240 1.36
9 Esteban Ocon Force India 1:33.290 1.41
10 Stoffel Vandoorne McLaren 1:33.321 1.441
11 Fernando Alonso McLaren 1:33.530 1.650
12 Lance Stroll Williams 1:33.538 1.658
13 Kevin Magnussen Haas 1:33.787 1.907
14 Nico Hulkenberg Renault Sport 1:33.871 1.991
15 Carlos Sainz Toro Rosso 1:33.924 2.044
16 Pierre Gasly Toro Rosso 1:34.206 2.326
17 Jolyon Palmer Renault Sport 1:34.475 2.595
18 Romain Grosjean Haas 1:34.914 3.034
19 Marcus Ericsson Sauber 1:34.936 3.056
20 Pascal Wehrlein Sauber 1:35.045 3.165