Verstappen was nearly half a second clear of the Spaniard and so good was his first lap in the final phase that he aborted the second once it became clear nobody else was going to beat him.
"The car was on rails," said the happy Dutch driver, who took his first Formula One win at Barcelona's Circuit de Catalunya in 2016 and also triumphed last year.
"It was really enjoyable to drive today."
McLaren's Lando Norris qualified third in a dramatic and surprising session with Alpine's Pierre Gasly fourth but under investigation for two counts of suspected impeding.
Red Bull's Sergio Perez, Verstappen's closest title rival but 39 points behind after six races, qualified only 11th while Ferrari's Charles Leclerc will start a shock 19th on the grid.
Seven-time world champion Lewis Hamilton will line up fifth for Mercedes.
Six different teams filled the top six positions, with Canadian Lance Stroll qualifying sixth and ahead of Aston Martin teammate Fernando Alonso, in ninth, for the first time this season.
The big shock after a first phase red-flagged due to gravel on the slippery track was provided by last year's pole-sitter Leclerc ending up on the back row.
"Unbelievable," said the Ferrari driver, who had complained earlier about a problem with his rear tyres, when his engineer confirmed the result.
Perez used the same word after the Mexican failed to make the cut for the top-10 shootout, having just scraped through the first phase.
Mercedes's George Russell was another casualty of the second phase, ending up 12th after also colliding with Hamilton at the end in a bizarre clash that drew the attention of the stewards.
"George just backed off," said Hamilton over the radio. "That's really dangerous."
Mercedes blamed the incident on a miscommunication, with Russell apologising and Hamilton requiring a new front wing for the final phase.
Several drivers, including Alonso, spun or ran into the gravel in a tricky opening phase that started with spits of rain and was halted with 14 minutes and 13 seconds remaining on the clock.
Gasly appeared to impede Sainz and Verstappen and risks a demotion.
