Leclerc and Verstappen both completed their laps as the flag waved, bumping Sainz from top spot by less than a tenth of a second.
It was close at the top, with Lewis Hamilton fourth fastest, also within a tenth of Leclerc.. Less than a second covered the field down to Yuki Tsunoda in 11th.
Oscar Piastri was eighth best, while Daniel Ricciardo was 18th in the 19-car field.
Practice 3 brought with it the first appearance of the Hard compound tyres of the weekend, with both Sauber’s bolting them on in the early minutes.
Following an installation lap, Lando Norris also sported the white-walled rubber in what was a quiet start to the final hour of running before qualifying.
In the early minutes, Max Verstappen complained of a lack of bite from his brakes.
On track with a set of medium compound tyres, it was clearly of little concern as he soon after recorded the best time of the session, a 1:18.591s.
The world championship leader was the second driver to log a lap, his Red Bull Racing team-mate Sergio Perez the only other driver on the board at the time with a 1:19.206s.
It was a subdued start, with only 11 drivers heading out in the opening 15 minutes of the session and only three of those completing timed laps.
The early laps on the hard tyres seemed to be little more than roading the rubber ahead of Sunday’s race as the medium quickly emerged as the preferred compound.
Alex Albon became the fifth driver to complete a timed lap when he logged a 1:19.461s for Williams.
His team-mate has been scratched from the weekend after team boss James Vowles opted to switch Albon into the team’s sole remaining car for the balance of the event.
The Thai-licensed driver crashed during Free Practice 1, his car sustaining damage sufficient to rule it out for the balance of the weekend.
Without a spare, Vowles made the tough decision to pull Sargeant out in favour of dropping Albon back in.
After 20 minutes, the entire field had been on track, with some turning their focus to qualifying simulations.
There was confusion at Mercedes, with the team advising Lewis Hamilton he was over a second off the pace, prompting the seven-time world champion to ask where he was losing time.
Hamilton’s best at the midway point was a 1:17.554s on the soft tyres, seven-tenths down on Carlos Sainz, who sat atop the timesheets on a set of medium tyres.
Charles Leclerc sat second best with Verstappen shuffled back to third, the Dutchman having improved to a 1:17.100s.
With 20 minutes remaining, the circuit fell quiet with just four cars on track.
One of those was Piastri, who was 10th fastest at the time, his qualifying simulation seeing him improve to seventh with a 1:17.559s.
A second push lap saw the Australian rise to third with the same time as Leclerc – the Ferrari driver having managed his 1:17.087s earlier and therefore scored ahead of the McLaren.
“It’s amazing what happens when you stop being an idiot at Turn 1,” Piastri responded when told of his relative pace over the radio.
In the other McLaren, Lando Norris could only manage seventh fastest with his flying lap, a 1:17.490s.
Hamilton found the time he lacked earlier in the session as he clocked the second-fastest time with his performance run, 0.015s down on Sainz.
The Ferrari driver still had not completed his own qualifying simulation yet remained fastest, with team-mate Leclerc and the Red Bull Racing pair in the same boat.
When Verstappen did, it was an effort best described as steady as he recorded a 1:17.100s, a lap bettered by George Russell in the second Mercedes.
Inside the final 10 minutes of the session, a flurry of activity looked set to see Sainz draw further ahead, only for the Spaniard to abort the lap and return to the pits.
Verstappen had another attempt too, improving through a number of microsectors but failing to set the world alight, moving up only to fourth and 0.237s back from Sainz.
Leclerc was third best, o.033s away from his Ferrari team-mate, while Russell improved to demote Verstappen to fifth, the Brit 0.095s away from the top of the timesheets.
After Verstappen was Piastri, while Norris was only 10th for McLaren.
At RB, Yuki Tsunoda ended the session 11th best, 0.882s away from the outright pace, while Daniel Ricciardo was 19th and 1.172s off the front.
As the chequered flag flew, the order changed once more as Verstappen shot to the top of the timesheets before he was knocked back a peg by Leclerc.
It left the ultimate pace at 1:17.714s, Verstappen 0.020s slower and Sainz third 0.077s away from his team-mate.
Hamilton in fourth was also within a tenth of the pace in a session that saw the top 11 covered by less than a second.