The British driver has outperformed his teammate at each of the past five race weekends.
Lando Norris narrowly beat fellow driver and title rival the Australian for the fastest time in the dying seconds of the practice session at the Brazilian Grand Prix.
Norris, who took the championship lead from his teammate by a single point after taking the win in the Mexican Grand Prix two weeks ago, topped the Melbourne-born driver by 0.023 seconds.
Earlier in the session, Piastri had been the fastest McLaren driver throughout the hour before sprint qualifying due at the evening session.
Max Verstappen, the other racer in realistic title contention, trailing with a 36-point deficit behind Norris, was classified in 17th position as his team opted for a unique setup.
His teammate the Japanese driver was the only driver to crash, though minor, when he spun at corner four during the early running.
Tsunoda lost control over the curbs on exit before sliding over the gravel trap, and was fortunate to escape with just a minor contact of the wall.
Ferrari's Lewis Hamilton also lost it, at the very end of the session, rotating twice through the high-speed corner leading to the final corner on to the main straight.
The veteran ended the session in 19th, just behind teammate the Monegasque driver.
Norris and Piastri were well clear of the remaining drivers, with the German's Sauber P3, 0.619 seconds off the Australian's time.
Aston Martin's the Spanish driver was fourth fastest, with Sauber's Gabriel Bortoleto ahead of the Mercedes of Russell and Alpine's Gasly and the Williams of Carlos Sainz.
Elena Vance is a logistics consultant with over a decade of experience in transport management and supply chain optimization.