Verstappen was pinched between the Ferraris of Vettel and Kimi Raikkonen on the run to the first corner, causing all three cars to collide and resulting in a secondary incident that also collected Fernando Alonso.
"I've got no idea -- and that is the concern I've always had with this race", Romain Grosjean told Autosport.com earlier, when asked if it would be safe to race in the rain. "But I'm sure there'll be more opportunities". "The quickest vehicle and the quickest driver were out within a minute into the race and that can happen all the time".
The Briton was promoted into the lead of the race when Vettel - who also got caught up in the opening lap clash - lost control of his Ferrari and spun into the wall on the exit of Turn 3 and retired.
"It's bitter but it's done", said the German, a four times Singapore GP victor, whose retirement ended a run of 18 successive points finishes and left him with a mountain to climb.
Fernando Alonso finds himself the innocent victim at turn one – Credit Octane
Lewis Hamilton believed he could claim an unlikely Singapore Grand Prix victory as soon as rain started to fall in the build-up to the race.
The incident brought out the safety vehicle and allowed Hamilton into a lead he would keep through two more safety auto periods and a perfectly-timed switch to dry weather tyres.
"Obviously it sucks being on the wrong side of the track now, but that's what it is", Vettel shrugged after returning to the paddock.
But Hamilton shot off after the restart to maintain the gap from Ricciardo and as he finally took the chequered flag, the grandstand came to its feet and fireworks lit up the night sky.