Frederic Makowiecki posted a lap of 1m41.223s in the #5 Porsche Penske Motorsport-entered 963 LMDh with fewer than 30 minutes left on the clock, dislodging the #94 Peugeot 9X8 that had led the way since the early part of the session.
The two factory Peugeot cars held the top spots for majority of the three-hour running, with a 1m41.260s lap from newly promoted former reserve driver Stoffel Vandoorne putting the #94 car three tenths ahead of the sister entry crewed by Jean-Eric Vergne.
That was until both works Porsches switched to qualifying simulations at around the 2h20m mark, with first Kevin Estre in the #7 963 splitting the two Peugeots and then Makowiecki also going quicker than Vergne's #93 9X8.
Makowiecki would then find another two tenths on his next flying lap to end the session on top, beating Vandoorne’s earlier benchmark by just 0.037s.
The #6 Porsche held on to third with Estre, while Vergne ended up fourth in what was still a strong showing for the 9X8 that is due to receive a major upgrade at the second round of the WEC in Imola in April.
Fifth place went to the #2 Chip Ganassi-entered Cadillac courtesy of Sebastien Bourdais’ time of 1m41.652s, which put him just over a tenth clear of Nyck de Vries in the best of the works Toyotas, the #7 GR010 HYBRID.
The customer Jota squad that topped the first two legs of Prologue was only seventh in the third session, with Callum Ilott’s time of 1m42.083s around 1.5s slower than what he had managed in considerably cooler conditions on Monday evening.
Ilott, a previous member of the Ferrari Driver Academy, shaded the Italian marque’s #51 499P Hypercar entry driven to eighth place by factory driver James Calado.
The top 10 was completed by the customer AF Corse Ferrari of Yifei Ye and the top #20 BMW M Hybrid V8 of 2022 DTM champion Sheldon van der Linde.
BMW was the fastest of the manufacturers new to the WEC this year, with the best of the Alpine A424 cars only 12th with Nicolas Lapierre at the wheel and the sole Lamborghini SC63 entered in conjunction with Iron Lynx languishing in 17th, 1.6s off the pace.
The 19-car Hypercar class field was propped up by the last of the newcomers, the Isotta Fraschini’s Tipo 6 Competizione, with Jean-Karl Vernay finishing three seconds slower than the pace set by Porsche.
Aston ahead in LMGT3
In the LMGT3 class, it was Aston Martin that led the way courtesy of a late flier set by Marco Sorensen in the new-for-2024 Aston Martin Vantage GT3.
Sorensen, driving for D’station Racing, posted a time of 1m54.791s in the #777 Vantage GT3 to eclipse the previous benchmark set by Davide Rigon in the #54 AF Corse Ferrari 296 GT3.
Daniel Juncadella ended up third in the #82 TF Sport Corvette Z06 GT3.R, despite having set his fastest lap - which was only 0.015s slower than Rigon - right at the beginning of the session.
After leading the first two parts of the Prologue, United Autosports finished fourth in the LMGT3 order with former Formula 2 driver Marino Sato at the wheel of its #95 McLaren 720S GT3.
Sato, however, breached the track limits at a number of occasions, picking up a 10-minute stop-and-go penalty for the Prologue.
Fifth place in class went to Ian James in the #27 Heart of Racing Aston Martin, as the top five were separated by just a quarter of a second in an ultra-competitive session.
15 out of 18 LMGT3 class finished within two seconds of each other, with only the two ASP Lexus RC G GT3 entries and Proton’s #77 Ford Mustang GT3 missing that cut.
The third session was red-flagged twice due to maintenance and track cleaning. The first red flag was waved just after an hour, while another caution period followed 1h45m into the session for the same reason.
Three more hours of running is scheduled in Qatar this evening, but the session will be limited to only those cars that skipped the opening part of Prologue on Monday afternoon.
