The Monegasque driver started from pole and, having lost out early on to both Lando Norris and Lewis Hamilton, was the only driver in the field to run a one-stop strategy.
He eventually slipped back to sixth place, although that became academic when he was disqualified for a plank infringement.
Meanwhile, from fourth on the grid, his team-mate Carlos Sainz followed the rest of the field in stopping twice on his way to an initial fourth place in sight of Norris. That became third when runner-up Hamilton was disqualified.
Speaking before the disqualifications changed the final results, Vasseur conceded that the team had got it wrong with Leclerc.
"Clearly we have mixed feelings," he said when asked about the race by Autosport. "Because on one side of the garage with Carlos, we did pretty well. Starting P4, finishing P4, we finished two or three seconds behind Norris, and I think everything went well.
"With Charles, who was 10 seconds in front of Carlos after 12 laps, we committed for one stop, and it was not the good choice, it's obvious.
"Probably the issue is that we didn't have a clear picture about this before the race, we were a bit hesitating, and he was a bit hesitating into the first stint, pushing or not pushing. And we made a mistake.
"It was not very clear before the race, as you can imagine. We had the two options. In terms of numbers, it was very, very close.
Source: Autosport