With a 1m40.203s lap at the close of the session, Leclerc chalked up his first pole of the season - his 19th in F1 - to beat the Red Bulls of Max Verstappen and Sergio Perez to the punch.
Leclerc admitted his surprise at beating the brace of RB19s to the front of the grid, but he explained that much of the groundwork had been laid by the team during the Australian Grand Prix weekend.
Although Ferrari failed to score at Albert Park, owing to Leclerc's early retirement and Carlos Sainz's penalty for causing a final restart clash with Fernando Alonso, the team made good strides with its SF-23 amid a difficult start to the year.
Leclerc added that he felt much of Ferrari's issues in Australia had been of his own making, masking the set-up gains that the Scuderia had been able to acquire throughout the previous round.
"One thing for sure is that I think we did a step forward in Australia; on my side I obviously couldn't show it, but on Carlos's side, I think the feeling was much better during the race.
"Then how much better [we are in the race] we still need to see on Sunday. So I think on that, we still have some question marks, but I am absolutely sure that we did some steps in the right direction. I'm not sure whether it's enough [to beat Red Bull] though.
"I think there's been a good step in terms of set-up. The qualifying since the beginning of the season hasn't been that bad.
"I think in Australia, we didn't do a great job, I think I did not drive well. Before that, we weren't that far off, so I think we gained a little bit in qualifying.
Source: Autosport