An unusual error at the end of his first flying lap in the third qualifying session left him with just one shot on pole in the death.
But he kept his composure to become the only man to go under 1:19 for a lap with a time of 1:18.750. He had appeared destined for a qualifying shootout with Max Verstappen but the Dutchman complained of a loss of power and was sent back to the pits.
While there was familiarity with the front row of the grid, Mercedes had threatened to enter the mix at the top of the timesheets as Lewis Hamilton and George Russell briefly swapped the lead in Q2.
But despite their improvements for Barcelona, which rectified their porpoising and improved their running pace, it wasn’t quite the moment of euphoria many were hoping for. In the end, they are still far from the pace of Ferrari but there are still reasons for optimism.
Russell once again got the better of his more experienced team-mate to qualify fourth behind Carlos Sainz with Hamilton sixth behind second-placed Red Bull Sergio Perez.
Following his pole on a circuit where overtaking is traditionally rare, Leclerc said: “I am in a strong position to start the race. But we struggled with the tires at the start. We have to get on top and do a good job with tire management. We will give it our all. But I am very, very happy with pole position.
Verstappen wondered what might have been without the loss of power, although the Red Bull has been behind the Ferrari so far this weekend. But he goes into Sunday’s race knowing that the Red Bulls have been kinder to the Pirelli tyres.
The race is likely to put a strain on the rubber with track temperatures reaching nearly 50 degrees during qualifying and potentially higher temperatures on race day.
Both Haas drivers entered Q3 for the first time with Kevin Magnussen in eighth and Mick Schumacher in 10th. Former Hamilton team-mate Valtteri Bottas finished seventh with Daniel Ricciardo the other top 10.
It turned out to be a topsy-turvy session with three teams trading first place on the timesheets in front of a crowd of 110,000.
There was disappointment in the crowded stands as home favorite Fernando Alonso failed to make his way out of the first qualifying session after being held up in traffic. Stewards briefly considered the possibility that he was hampered by Lando Norris but decided no further action was necessary.
The big surprise to emerge from the second qualifying session was McLaren’s Norris, his lap time erased after overshooting the track limits at Turn 12, before Leclerc dominated the final with his lap to the death.