Surprisingly, 18-year-old Italian Kimi Antonelli topped the session, with Hamilton's Mercedes replacement beating his seven-time world champion predecessor.
New Red Bull driver Liam Lawson brought his car home in second, with Williams' Alex Albon in third. Hamilton could only set a time fast enough for fifth in the Ferrari, although times are not the priority for teams this early on in the week.
Meanwhile, it was Max Verstappen's new team-mate Lawson who suffered the most dramatic moment of the four-hour session, experiencing a huge spin, narrowly avoiding putting his RB21 into the barriers.