Sainz will start ahead of Max Verstappen (Red Bull) and Charles Leclerc (Ferrari) in Sunday’s race after the one-hour qualifying session on Friday, which is split into three segments with five cars each being knocked out in Q1 and Q2 before the top-10 shootout of Q3.
As per the alternative tyre allocation rules, this session was run on the hard rubber. After having a lap time deleted for exceeding track limits, Verstappen set the quickest time of 1m21.573s.
Both Ferraris were pinged for not adhering to the minimum lap times in this session, and faced a stewards inquiry that decided no further action.
Falling at the first hurdle were Zhou Guanyu (Alfa Romeo), the Alpines of Pierre Gasly and Esteban Ocon (who suffered a trip through the gravel at Ascari), Kevin Magnussen (Haas) and Lance Stroll (Aston Martin).
On medium tyres, Sainz set the early pace at 1m20.991s, 0.044s ahead of Verstappen.
Leclerc beat that with 1m20.977s on his final run but Verstappen then topped both Ferraris with a last-gasp 1m20.937s to deny a Ferrari 1-2 by 0.04s.
Knocked out at this point were the AlphaTauris of Yuki Tsunoda (who failed to progress by just 0.013s) and Liam Lawson, Nico Hulkenberg (Haas) and Logan Sargeant (Williams).
On soft tyres, Ferrari took an early 1-2 with Sainz setting the pace at 1m20.532s, 0.032s ahead of Leclerc. Verstappen was only third after running wide on the exit of Roggia, which cost him a vital tenth.
Pole changed hands three times in the final seconds as Leclerc produced 1m20.361s, which was beaten by Verstappen’s 1m20.307s and then Sainz unleashed 1m20.294s, taking the top spot by 0.013s.
George Russell will start fourth for Mercedes, ahead of Red Bull’s Sergio Perez, Alex Albon (Williams), Oscar Piastri (McLaren), Lewis Hamilton (Mercedes), Lando Norris (McLaren) and Fernando Alonso (Aston).