Ferrari considered swapping Sebastian Vettel and Charles Leclerc on-track during the second stint of the Singapore Grand Prix after underestimating the power of the undercut in the race, according to team principal Mattia Binotto.

Vettel scored his first win in more than a year on Sunday at Marina Bay after jumping from third to first through his pit stop, getting the undercut after pitting one lap before early race leader Leclerc.

Leclerc was left frustrated by his loss of the lead to Vettel, saying over team radio that it was "not fair" and that he wished to discuss what had happened after the race.

Ferrari team chief Binotto explained that the strategists had underestimated how much Vettel would gain by pitting one lap earlier than Leclerc, believing the move was the correct one to stay ahead of Max Verstappen and attempt to pass Lewis Hamilton in second place.

"The undercut was effectively more powerful than expected, it was 3.9 seconds. We were not expecting such a big number," Binotto said.

"As a matter of fact, when we stopped Sebastian, we thought when Charles stopped the lap after, he would be ahead of Sebastian. Sebastian drove well, got the undercut of 3.9 seconds - that’s the difference."

Binotto went on to confirm that Ferrari did consider asking Vettel to give the position back to Leclerc during the second stint of the race.

"Did we consider the swap? Yes, we did," Binotto said.

"I think we thought at that stage at least it was the right choice not to do it, and obviously now, we are still discussing with the drivers if that was the right choice or not, which internally we still have different opinions to discuss.

"But yes, we thought about it."

Asked by if he understood why Ferrari's strategy had unfolded as it did, Leclerc offered a calmer response than his initial frustration over team radio.

"I think we have been surprised by how powerful the undercut was. As I said, in the car it was very frustrating, but now out of the car I understand a lot more the whole situation," Leclerc said.

"I’m extremely happy for the team, very happy for Seb too, he deserves it, and now I will move forward.

"Obviously I wish I was one step higher today, but it’s part of life. Sometimes it goes that way, and I will bounce back stronger in Russia."