He regained his position at the top of the Formula One world championship, but Lewis Hamilton isn't getting ahead of himself after victory at the French Grand Prix.
Vandoorne, who ended up 19th in a "learning" session, had also been a spinner as he searched for the limits of the track.
A wheel then came off Sergio Perez's Force India vehicle at speed on the Mistral straight in the late afternoon.
The revamped Paul Ricard circuit at Le Castellet was a fixture on the F1 calendar until 1990, when four-time champion Alain Prost won the last race held there for Ferrari.
The Mercedes team's form reflected their determination to bounce back after a disappointing showing in Canada, two weeks ago, where Vettel's 50th career win put him back on top. We can be happy with third for tomorrow (though). "It is such a handsome place", he added.
US Stocks Open Higher on Bargain Hunting
Among the day's losers, the yuan weakened to 6.491 to the dollar in the offshore market, the lowest in five months. Beijing has mounted campaigns against Japanese and South Korean companies in the past after diplomatic disputes.
Hamilton's Finnish team mate Valtteri Bottas, also with a new Mercedes engine in his vehicle, was second fastest in the initial stint but seventh in the second after his auto developed a water leak. Quite how the Dutch 20-year-old deals with a new track remains to be seen as Red Bull try to get the most out of their Renault engine before switching to Honda from next year.
The 90-minute opening session was red-flagged with a minute remaining when Ericsson lost control at the Beausset corner, spun and hit the barriers hard, with the Sauber auto then catching fire.
Bottas is third on 86, with Ricciardo fourth on 84 and Kimi Raikkonen fifth as the battle for supremacy among the drivers hits fever pitch.
British cyclist Adam Yates rode the circuit before qualifying - he will contest this year's Tour de France - Lance Stroll loved his time in the rain during a wet final practice.
"I think the vehicle is quick, but I wasn t able to be quick", he said. Another driver on somewhat of a high is Fernando Alonso, albeit not because of his faltering McLaren.
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