Leclerc had a solid first stint on the medium tyre despite missing a front wing endplate after a first-corner clash with Sergio Perez.
He pitted for hards just a couple of laps before Kevin Magnussen’s crash brought out the red flag.
During the break Ferrari replaced his damaged front wing but rather than switch to medium tyres for the restarted second half of the race, as some rivals did, the team stuck with the hards.
However, Leclerc couldn’t get the tyres in the right window, and he was quickly passed for second by Lewis Hamilton – who did go for mediums – before falling back.
Leclerc and team-mate Carlos Sainz eventually finished third and fourth, having qualified on the front row.
Red Bull believed that Leclerc would opt mediums during the red flag break, which could have given him a chance to jump poleman Max Verstappen, who also kept his hards, at the restart.
“I was convinced they were going to take a set of mediums because it’s worth about five metres off the startline,” said Christian Horner.
“So I was very surprised that they went with the hard tyre. We saw the medium on Hamilton, and it was ok in the end.”
Vasseur said the race had looked good for Leclerc initially, despite the compromised front wing.
“My feeling from the pit wall is that the first stint was okay,” said the Frenchman. “We were three or four-tenths from Max, with the damage on the car, it was I think almost a good stint.
“But with the hard, we were never able to restart the tyres, and we were always on the shy side, and it didn't work at all."
Asked if mediums had been an option, he said: "Honestly not, because think we had to restart for 35 laps or something like this. And we were not expecting to be able to do 35 laps.
“And I think Max also with the medium. Probably the tyre management, due to the management of the engine and the brakes and so on, helped [others]. But it was ambitious. And the set of medium that we had was a scrubbed one.”
Vasseur denied that it was frustrating that once again the team could not back up its qualifying form with good race pace.
“Frustrating is not the right word. When you are third and fourth, I don't want to say that it's a bad race.
“We had a bad stint at the end, this is clear, it's the main issue today. But the first part of the race went very well.
“I think that we are doing a step for a while now, we did the four pole positions out of the last six races. It's a step forward for us and we have to be probably bit more consistent on the race or at least to have no delta between those stints because it's very often where we are losing the position."
Vasseur did not blame Perez for the first-corner contact with Leclerc.
"I think that the issue is that when you have this situation on the start and you are three on the same line in Turn 1, I think it's almost the same outcome,” he said.
“They asked me if it was a sandwich, and I told them that it was more a panini for us!
“At the end when you are three like this you can't blame Checo to close, and Max can't go on the kerb, and Charles was in the middle."
