The British driver has outperformed his teammate at each of the previous five grands prix.
Lando Norris edged out team-mate and championship contender the Australian for the quickest lap in the closing stages of practice at the Sao Paulo Grand Prix.
Norris, who took the championship lead from Piastri by just one point after winning in Mexico City two weeks ago, topped the Australian by 0.023 seconds.
Before then, Piastri had been the leading McLaren during the running before the sprint shootout scheduled for the evening session.
Max Verstappen, the only other driver in the championship fight, sitting 36 points behind behind Norris, finished in P17 as his Red Bull team ran a alternative strategy.
Verstappen's team-mate the Japanese driver was the only driver to have an incident, albeit lightly, when he rotated at the fourth corner early in the session.
The Japanese slid over the curbs on exit before sliding over the escape zone, and was lucky to escape with just a light touch of the fence.
The Ferrari of Lewis Hamilton also had a spin, at the final moments of the session, turning around through the high-speed corner before the final bend on to the start-finish straight.
Hamilton wrapped up in 19th, trailing teammate the Monegasque driver.
Norris and Piastri were significantly quicker of the remaining drivers, with the German's Sauber P3, 0.619 seconds off Piastri's pace.
The Aston Martin of the Spanish driver was fourth fastest, with the Sauber of Gabriel Bortoleto fifth from the Mercedes of Russell and Alpine's Gasly and the Williams of Sainz.
Eleanor Hayes is a data scientist and business analyst with over a decade of experience in transforming raw data into actionable insights.