Nico Rosberg and Lewis Hamilton claimed the 1-2 at Spa on Friday afternoon but it was a session that ended in a red for the German as his right-rear exploded.
On a warm and near cloud-less afternoon at the Spa-Francorchamps circuit, Rosberg set the pace on the medium Pirelli tyres before doing the same on the softs.
The Mercedes driver, last year's Belgian GP pole-sitter, clocked a 1:49.385 to edge his team-mate Hamilton by 0.302s.
But back out on track later in the session, putting in a long distance heavy fuel run, Rosberg's W06 suffered a right-rear tyre blowout at very high speed.
That pitched him into a spin followed by a slide at Blanchimont but thankfully he managed to avoid the barriers.
The session was red-flagged as the marshals removed his car and swept the debris from the track.
Rosberg, who had done 11 laps on that set of the soft tyres before the incident, said he was not aware of having run over any debris to close the failure.
FP2 resumed with 15 minutes remaining on the clock and three minutes later it was back under red, this time for Marcus Ericsson.
The Swede touched the kerb on the exit at Pouhon with the accident ending with his C34 in the barriers.
The car sustained heavy damage, front and rear, but Ericsson reported that he was "okay" to his pitwall. He added: "I hit the wall hard, I'm sorry guys."
The session restarted, giving the drivers five final minutes of running.
Daniel Ricciardo, who won last year's Belgian GP, put Red Bull into the mix as he finished the afternoon in third place, 0.751s down, while Daniil Kvyat was fourth.
Kimi Raikkonen, fresh from signing a new Ferrar contract, was fifth ahead of Nico Hulkenberg and Romain Grosjean, whose Lotus broke down out on track as the chequered flag was waved.
It was a good session – prior to the crash – for Sauber as Ericsson and Felipe Nasr, both powered by upgraded Ferrari engines, were eighth and ninth ahead of Sebastian Vettel.
Two incidents will be investigated after the session. The first involves Romain Grosjean and Nico Hulkenberg and impeding while second relates to Red Bull's unsafe release of Kvyat which forced Felipe Nasr to break hard in the pitlane.
1 Nico Rosberg Mercedes 1:49.385 20 laps
2 Lewis Hamilton Mercedes 1:49.687 +0.302 23 laps
3 Daniel Ricciardo Red Bull 1:50.136 0.751 16 laps
4 Daniil Kvyat Red Bull 1:50.399 1.014 19 laps
5 Kimi Raikkonen Ferrari 1:50.461 1.076 24 laps
6 Nico Hulkenberg Force India 1:50.461 1.076 22 laps
7 Romain Grosjean Lotus 1:50.489 1.104 21 laps
8 Marcus Ericsson Sauber 1:50.709 1.324 19 laps
9 Felipe Nasr Sauber 1:50.928 1.543 24 laps
10 Sebastian Vettel Ferrari 1:50.940 1.555 24 laps
11 Sergio Perez Force India 1:50.971 1.586 22 laps
12 Carlos Sainz Toro Rosso 1:51.037 1.652 25 laps
13 Max Verstappen Toro Rosso 1:51.117 1.732 26 laps
14 Valtteri Bottas Williams 1:51.250 1.865 26 laps
15 Pastor Maldonado Lotus 1:51.317 1.932 17 laps
16 Felipe Massa Williams 1:51.588 2.203 27 laps
17 Jenson Button McLaren 1:51.854 2.469 17 laps
18 Fernando Alonso McLaren 1:52.570 3.185 14 laps
19 Will Stevens Manor 1:54.065 4.680 18 laps
20 Roberto Merhi Manor 1:54.253 4.868 15 laps