Verstappen shows stomach for fight as Red Bulls dominate
The defending double world champion clocked a fastest lap in one minute and 29.617 seconds to outpace Perez by four-tenths of a second, the champion team stamping their authority in the heat at the Jeddah Street Circuit.
Two-time champion Fernando Alonso followed his bold third place at the season-opening Bahrain Grand Prix by taking third ahead of his Aston Martin team-mate Lance Stroll.
The two Mercedes, running with various upgrades, were fifth and sixth, George Russell narrowly outpacing seven-time champion Lewis Hamilton, with Carlos Sainz seventh for Ferrari.
Pierre Gasly of Alpine was eighth ahead of Alex Albon, in his improved Williams, and Yuki Tsunoda, 10th for Alpha Tauri.
Charles Leclerc was 11th in the second Ferrari.
Hamilton ruffled some at Mercedes Benz when he declared this year's machine was 1.5 seconds per lap slower than Red Bull in race trim, a deficit the team were seeking to overhaul.
"He's shaking the tree and he wants a reaction," said the 1996 world champion Damon Hill on Sky Sports.
With an air temperature of 28 degrees Celsius and the track at 44, Sainz led the early pace-setters, on soft tyres, before Alonso, also on softs, and then Hamilton, on hards, took over.
After five minutes, everyone had been out except for Verstappen and Stroll, still recovering from his pre-season wrist injuries.
Perez showed that Red Bull were not being left out when he went top after 15 minutes, a second clear of Albon, with a lap in 1:31.486.
For a short spell, Alonso and Perez traded fastest laps before Verstappen, recovered from his stomach bug, swept to the top on his second lap in 1:30.494, trimming it 1:30.062 to move almost half a second clear of the Aston Martin.
After half an hour, it was Verstappen ahead of Alonso, Perez and Russell, with the two Ferraris, both using newly-installed power units, eighth and ninth, more than a second off the Dutchman's pace even before Verstappen extended his gap at the front to seven-tenths.
With five minutes remaining, Stroll ran off at high speed but avoided the barriers. Lando Norris, running a new engine in his McLaren, was shown a black-and-white flag for failing to follow the instructions of the race director.
The session was preceded by an announcement from Hamilton that he had split from long-term personal trainer Angela Cullen after more than seven years, the New Zealander moving on to pursue new adventures.
"For the last seven years, Angela Cullen has been by my side, pushing me to be the best version of myself," said Hamilton in an Instagram post. "So today I hope you'll join me in wishing her the very best as she takes her next steps to pursue her dreams."