Norris set a best time of one minute 30.132 seconds on soft tyres, 0.024secs ahead of Piastri, who was standing in for Daniel Ricciardo as the Australian recovers from Covid-19.
Leclerc was third, 0.076secs behind Norris, with Sainz 0.113secs off the pace.
World champion Max Verstappen was fifth fastest, 0.153secs behind Norris, with Alpha Tauri’s Pierre Gasly seventh and Alfa Romeo’s Valtteri Bottas eighth.
McLaren’s pace was impressive given that neither of their drivers had raced at the Jeddah Corniche Circuit before this weekend.
The team have been in strong form in recent races, with Norris finishing second and Ricciardo third in the Australian Grand Prix two weeks ago.
But they have not had the out-and-out pace of the Red Bulls and Ferraris, and the performance in practice suggests they are in the mix at least for the race on Sunday.
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