This is the first time that Hamilton and Bottas have put their Mercedes cars in the front all season.
Later in the race Verstappen was running fourth when he clipped his front wing on a Williams under the virtual safety vehicle, but the damage was not significant and he didn't have to make an extra stop.
Vettel has secured the last three pole positions as the Ferrari established itself as the fastest vehicle in the early stages of the new season. He was 0.132s behind Hamilton. He needed to perform at his best, pushed to the line by Bottas who finished just four-hundredths of a second back.
"I think we need to admit that they were just a bit quicker today", said Vettel. May have looked wrong, but it wasn't. "We're not engineers but at the end of the day we're the ones that know what's going on in a racing situation".
BC-CAR-F1-Spanish GP, 6th Ld-Writethru, 739 Hamilton takes pole for Spanish GP with track recordAP Photo XLB163, XLB169, XLB152, XLB143, XLB137, XLB144, XLB145, XLB146, XLB151, XLB155, XLB150Eds: Updates with quotes by Ricciardo, Magnussen.
During pre-season testing at the Circuit de Catalunya, a number of teams - most notably Mercedes - struggled with excessive overheating and blistering on the circuit's newly-laid track surface. Raikkonen was sixth, despite the power issue, with Stoffel Vandoorne ninth in his McLaren and Sergio Perez rounding out the top ten in his Force India.
The race started with high drama as Grosjean made an inexplicable error.
The Ferrari team ran with a package of upgraded new parts on their cars including rear-view mirrors set on their halo head protectors.
Grosjean faces an investigation by the stewards and could be penalised. The Frenchman spun across the track, kept his foot down on the throttle and was collected by Hulkenberg and Gasly.
"I chipped away at my lap time by a few hundredths but it wasn't enough", Ricciardo said. "He has to look at it and do some work on himself".
There was no messing around from Hamilton at the start of Q3 as he claimed provisional pole on his first lap and never relinquished the position.
"The plan for free practice one was no different to if Sergey had been in the vehicle", stated the team spokesperson.
Monaco in two weeks' time.
The Australian's session was instantly over as he hitched a lift to the pits and his damaged auto was taken on a truck back to the Red Bull garage for repairs.
"My personal feeling in the vehicle is not 100 per cent good", he told RTBF television. "So, we saw lots of drivers going off". A one-two for the team.
In cooler conditions, the session was brought to an early conclusion when New Zealander Brendon Hartley lost control of his Toro Rosso vehicle at Turn Nine and spun violently into the barriers.