Championship leader Valtteri Bottas completed a hat-trick of pole positions Saturday when he outpaced his Mercedes team-mate Lewis Hamilton in a tightly-contested qualifying for Sunday's Spanish Grand Prix.
The Finn, who leads defending five-time champion Hamilton by a single point in this year's title race, completed a treble after taking the prime grid position in both China and Azerbaijan.
Bottas clocked a stunning track record lap in 1min 15.406sec to finish six-tenths clear of his teammate in the top 10 shootout on a dry and gusty day at the Circuit de Catalunya.
With Hamilton second, it gave Mercedes another front row lock-out and suggested this year's title race may become a duel between the two Silver Arrows drivers with Bottas currently enjoying the momentum.
Four-time champion Sebastian Vettel of Ferrari was third ahead of Max Verstappen of Red Bull, Charles Leclerc in the second Ferrari and Pierre Gasly in the second Red Bull.
Romain Grosjean was seventh ahead of his Haas teammate Kevin Magnussen, Russian Daniil Kvyat of Toro Rosso and Daniel Ricciardo in his Renault.
"I really enjoyed that," said Bottas. "The adrenaline rush you get from laps like that is great so I am really pleased.
"The season has started well, the way I hoped for, and I feel better in the car."
Hamilton congratulated Bottas and conceded that he had been unable to extract the maximum from his car on a circuit where he was hoping to land his own hat-trick of three straight Spanish poles.
"My final laps in Q3 just weren't strong enough. Ultimately, I didn't do the job," Hamilton said.
"It's great to have another Mercedes 1-2, but I can reverse it tomorrow that would be great."
Vettel was also disappointed as Ferrari failed to deliver the pace that could bring an end to Mercedes domination.
"The car doesn't feel too bad, but obviously we are not quick enough," he said. "It seems to be more than an achilles heel here... I spoke to Valtteri and they were happy with their car."
In cooler conditions than on Friday, the opening Q1 session saw several cars struggling for grip, not helped by a gusty wind.
Nico Hulkenberg ran off track in his Renault at turn four and after traversing a gravel-trap hit the barriers. He managed to recover and, after pitting for a new front wing, rejoined the fray.
His efforts were in vain, however, and he was eliminated in 16th place along with Lance Stroll of Racing Point, Antonio Giovinazzi of Sauber and the two Williams men, British rookie George Russell and Robert Kubica.
"Thanks again everyone for getting the car ready and apologies for FP3," said Russell on team radio, referring to his final practice crash that required a gearbox change and will land him a grid penalty.
As if to signal his intentions, Hamilton was first out for Q3, but it was Bottas who showed the way in 1:15.406 to take pole on his first run, six-tenths ahead of his Mercedes teammate.
