Mercedes Formula E driver Vandoorne is several seconds behind in second, while Formula 1 driver Max Verstappen, sharing with fellow F1 driver Lando Norris in the #20 Team Redline car, runs third after the Dutchman initially moved from fifth to third inside the opening lap.
The polesitting #4 ByKolles car led in the early stages with ex-Formula E driver Tom Dillmann at the wheel, but had to serve a drive-through penalty having being deemed to have jumped the start, rejoining down in 17th.
Elsewhere in the field, the Fernando Alonso/Rubens Barrichello #14 entry dropped well down the order after Alonso pitted for repairs and to serve a one-second penalty for a collision with the #94 Porsche driven by Simona de Silvestro on the entry to Tertre Rouge at the half-hour mark.
Other cars to suffer problems have been the #8 Toyota Gazoo Racing after Brendon Hartley spun off at Indianapolis, suffering extensive damage, while the #15 entry of father and son pairing Andy and Seb Priaulx have suffered from connection issues.
The GTE class is led by the #88 Dempsey Proton Racing Porsche with Loek Hartog by 10 seconds, followed by the #93 and polesitting Porsche driven by 2015 Le Mans 24 Hours winner Nick Tandy.
Motorsport.tv and Motorsport.com are streaming the entire event, with coverage starting from 1:30pm BST on Saturday. There will also be full coverage of all the action and updates across the Motorsport Network's websites and social media accounts