Valtteri Bottas took pole position for the Portuguese Grand Prix with seven-time world champion Lewis Hamilton completing a Mercedes front-row lockout in qualifying on Saturday.

Hamilton's pursuit of a 100th pole at the track where last year he notched up his record 92nd win was delayed when Bottas earned the 17th of his career.

"It's a good feeling to be on pole," said Bottas.

He added: "Feels like it's been a while. It's been a weak point for me in the first two races. The team have been working hard all weekend and we have a good position for tomorrow."

Red Bull's Max Verstappen, one point off Hamilton in the drivers' standings, took third on Sunday's grid with his teammate Sergio Perez alongside him on the second row in Portimao.

Carlos Sainz for Ferrari came in fifth ahead of the Alpine of Esteban Ocon, Lando Norris, in a McLaren, and Charles Leclerc in the second Ferrari.

Hamilton paid tribute to Bottas "and our team" for us both to be on the front row.

"It was not expected. We have to be happy for that, it was not the perfect lap but I gave it everything.

"You can never be satisfied, we exist to keep moving forward but I'm happy with what we're doing and the steps we're taking."

Hamilton narrowly leads the 2021 championship after he won the opener in Bahrain before his Dutch rival Verstappen hit back in the Emilia Romagna GP at Imola.

This weekend the Briton is joining the social media blackout featuring a host of international sports bodies as well as individuals in a protest over online abuse. (AFP)