Leclerc got off to the perfect start in Singapore, opening up a big gap ahead of Lewis Hamilton after the opening lap.
The Ferrari driver was still leading when the soft tyres began to fall off their cliff and the set of pit stops began to happen.
There was only three seconds separating the top five drivers, but crucially the hard tyres were going to be two seconds quicker on the outlap than those on old soft tyres.
With Leclerc leading, it looked as though he would have first point of call to get fresh tyres on first.
But Ferrari surprised everyone by pitting Vettel, who was driving in third behind Hamilton.
And it worked magically for the German with Leclerc coming out behind his Ferrari team-mate after his pit stop a lap later.
Leclerc was clearly baffled and furious with the decision, going on team radio to say “it’s not fair.”
He was still visibly upset after the race having missed out on a third consecutive win, but was more diplomatic in praising the team’s efforts in finishing a one-two.
It’s far from a fiery rivalry between Leclerc and Vettel such as the dynamic between Rosberg and Hamilton.
The two former friends often clashed in public rows causing headaches for Mercedes team bosses.
And Rosberg has praised Leclerc for the way he handled a situation which will have undoubtedly rubbed him up the wrong way.
“I think he was quite smart after the race,” he said on his YouTube channel.
“It’s a fine line to go full on in public complain, which is not the right way to do it.
“I myself have experienced some of those situations where it’s just a mistake because to go too strong in public is just wrong.
“But to do nothing in public is also wrong because you do need to set a tone and not make it too easy for your team to talk over you as a driver.
“So I think he found the balance right there.
“He questioned it a lot during the race and then after the race he didn’t speak about it at all and just congratulated and was very happy for the team to finish a one-two.
“Leclerc found the right balance there but inside there’s going to be fireworks.”
