Lancaster charged into the lead from the start, controlling a lock-up into the first corner and then extending a 3.2-second lead before the safety car was required to recover Stephane Richelmi's stranded car.
At the restart Lancaster's Hilmer car pulled away again, while poleman Tom Dillmann held up a big queue of cars as he was forced to start on older tyres than many of those around him.
ART driver Calado took a couple of laps to pass Dillmann, doing so with a brave lunge at Turn 4, with Racing Engineering's Fabio Leimer also passing him also on the exit.
Robin Frijns passed Felipe Nasr for seventh, but his move on Sam Bird a lap later ended in a spin at Turn 4.
With Dillmann dropping out with a transmission issue, it was Ericsson's turn to struggle on older tyres with a queue of cars behind him.
Nasr passed Bird at Turn 4 on lap 20, and eased past Ercisson a lap later for fourth. He chased down Leimer, but failed to get the last place on the podium by 1.7s.
Johnny Cecotto clashed with Bird at Turn 4, but came through to finish fifth, ahead of Alexander Rossi, Mitch Evans and Bird.