Lando Norris has beaten his teammate at all of the previous five grands prix.
Lando Norris edged out team-mate and title rival the Australian for the top spot in the final moments of the practice session at the Brazilian Grand Prix.
Norris, who took the championship lead from Piastri by just one point after winning in Mexico City recently, outpaced the Melbourne-born driver by a mere 0.023s.
Earlier in the session, Oscar Piastri had been the quickest of the McLaren pair for most of the session before sprint qualifying scheduled for the evening session.
Max Verstappen, the other racer in the points battle, sitting 36 points behind behind Norris, finished in 17th position as his Red Bull team followed a alternative strategy.
His teammate Yuki Tsunoda was the sole competitor to have an incident, if briefly, when he lost control at Turn Four during the early running.
Tsunoda lost control over the curbs on exit before spinning across the gravel trap, and was lucky to get away with just a light touch of the wall.
The Ferrari of Lewis Hamilton also lost it, at the conclusion of the session, rotating twice through the quick descending Mergulho turn approaching the last turn on to the start-finish straight.
Hamilton wrapped up in P19, just behind team-mate the Monegasque driver.
Norris and Piastri were significantly quicker of the remaining drivers, with the German's Sauber third fastest, 0.619secs behind the Australian's time.
Aston Martin's Fernando Alonso was in fourth, with Sauber's Gabriel Bortoleto ahead of the Mercedes of George Russell and the Alpine of Pierre Gasly and Williams' Carlos Sainz.
Elias Vance is a Canadian journalist and political analyst with over a decade of experience covering national affairs and policy developments.