The No.8 Toyota Gazoo Racing TS050 HYBRID trio claimed a famous win amid a variety of challenging rain and snow showers which hit the Belgian venue throughout an exhilarating and unpredictable race.
There were four safety car periods for deteriorating conditions through the six hours, and the race was eventually red-flagged with 11 minutes to go as the weather closed in once again.
In winning, Alonso, Buemi and Nakajima are one step closer to the 2018-19 LMP World Endurance Drivers Championship which they now lead by 31 points. This title will be decided at the Super Final of the season, the 24 Hours of Le Mans in June.
The pole-sitting No.7 Toyota Gazoo Racing car of Mike Conway, Kamui Kobayashi and José Maria Lopez led comfortably until just before the half-distance mark but lost 11-minutes and four laps in the pits after a sensor problem on their hybrid system had to be repaired.
Kobayashi was over 50-seconds in the lead when the issue occurred, and he was forced to pit. The car eventually finished in sixth place in the LMP1 class.
It was a day of celebration for Toyota Gazoo Racing as the Japanese manufacturer took the 2018-19 FIA World Endurance LMP1 Championship with a round to spare.
The No.3 Rebellion R-13 shared by Gustavo Menezes, Thomas Laurent and Nathanaël Berthon took second place overall after a close battle with the No.11 SMP Racing car of WEC debutant Stoffel Vandoorne and his teammates Mikhail Aleshin and Vitaly Petrov.
The No.17 SMP car of Sergey Sirotkin, Stephane Sarrazin and Egor Orudzhev placed fourth after its race was affected by a lost wheel in the second hour.
LMP2: DragonSpeed Takes First WEC Victory
The DragonSpeed crew of Pastor Maldonado, Anthony Davidson and Roberto Gonzalez claimed a first win in LMP2 after a stunning victory which the American team moulded in the second phase of the six-hour race.
Maldonado drove a stellar triple stint to surge ahead of early leaders, the No.38 Jackie Chan DC Racing ORECA 07 and the No.36 Signatech Alpine Matmut entry.
The third Safety Car period in the fifth hour saw a fired-up Maldonado pass Gabriel Aubry and Nicolas Lapierre during his remarkable charge.
The pole-sitting G-Drive Racing car of Jean-Eric Vergne, Job Van Uitert and Roman Rusinov took second place after Vergne was able to leapfrog both the Signatech Alpine Matmut and No.38 Jackie Chan Racing cars in the final two hours.
The first hours of the race saw both of these team entries lead at stages, but the shake-up of the order under Safety Cars and Full Course Yellow periods changed the shape of the hotly contested class.
As a result, the Signatech trio of Nicolas Lapierre, André Negrão and Pierre Thiriet slightly extend their lead in the standings to four points over Ho-Pin Tung, Stéphane Richelmi and Gabriel Aubry.
