That lifted him clear of Sebastian Vettel of Ferrari by nearly one-tenth of a second, with his Mercedes teammate Valtteri Bottas, who took pole past year, third ahead of Kimi Raikkonen in the second Ferrari.
Informed of his imminent stewards' investigation, Vettel defended his actions.
"I was making sure I had the gap but then all of a sudden I saw a auto coming at high speed and was like 'oh my God, is that someone coming on a lap?' So I went left, but he was going left".
"They think it's something that might have actually started in Mexico", said team boss Christian Horner. When the conditions are like that, it's not fair. "I wanted them to hurry up".
"Yes, I definitely don't want to win if it's given to me", he said. It's clear what happened. I think 18 was probably the best back in the day.
To do it in Brazil they need to outscore Ferrari by 20 points.
Fulham manager Slavisa Jokanovic calls upon players to put in more effort
But Klopp said he waits until after "a full night and morning" as "emotions are not good for analysis". Klopp knows his Reds have been very impressive since the start of the season.
Verstappen can still become the youngest driver to take a pole position on Saturday, but the 21-year-old played down the chances of that happening.
Given the speed at which Sirotkin approached Hamilton's Mercedes, the initial evidence suggested the Williams driver was on a flying lap, and Hamilton was caught napping. Seeing the Williams, Hamilton moved to the left to try and get off the racing line but Sirotkin went the same way before backing off once ahead of the Mercedes. "The pace doesn't seem too bad, so we just have to keep working on it and improving it", said Hamilton. And when you are on an out-lap... Valtteri (Bottas) was ahead of me and he was backing off to get his gap to I had to back off. I was trying to get out of his way and then he got to the corner and slowed up. Is that someone coming on a lap?' So I went left, but he was going left. "The last three races, they've been really quick, so it was going to take something quite special to overhaul them today". Max Verstappen out-qualified teammate Daniel Ricciardo by 0.002s, although the latter faces a five-place grid penalty for the new turbocharger Red Bull fitted to his auto on Friday.
Ericsson has been dropped by Sauber for next season and is to race in Indycars in the United States, although he will remain the team's reserve driver. Vettel's team-mate Kimi Raikkonen qualified fourth.
Haas were best of the rest in the morning, with Romain Grosjean and Kevin Magnussen seventh and eighth.
Fernando Alonso's F1 career continues to fade out with a fizzle, McLaren having the slowest auto in Brazil and the Spaniard able to put it only 18th. Lance Stroll was 19th, with the McLarens of Fernando Alonso and Stoffel Vandoorne either side of him and set for another hard race from the back end of the grid. Horner said it had been damaged in Mexico by a marshal spraying foam on the auto after he retired from the race. "And in Abu Dhabi it will be my last race, we will put in a lot of emotions and a lot of effort and we will be out in Q1 because there are no miracles from one race to another".
Cape Town - Despite having won the championship, Lewis Hamilton says he won't be called on to return the favour Valtteri Bottas paid him back in Russian Federation by handing his team-mate a race win. Obviously Ferrari are incredibly quick this weekend. It's not a massive run down to turn one but Ferrari are very good at their starts in general normally. I was like, "Okay, that was a good start".