Lewis Hamilton was left stunned at seeing Max Verstappen deliver a rare Italian Grand Prix qualifying performance ahead of F1's second sprint race of the season.
On a Mercedes track that benefits its top speed, Hamilton appeared comfortably on course for pole after finishing quickest in Q1 and Q2, with Verstappen and Red Bull left trailing.
Red Bull had never previously qualified inside the top four at Monza in the turbo-hybrid era, but on the first lap in Q3, a Honda train saw AlphaTauri's Pierre Gasly tow Verstappen's team-mate Sergio Perez, with the Dutch driver pulled along behind.
That propelled Verstappen to within 0.017s of Hamilton, who was also quickest on the first lap in the session, and although failing to improve, the championship leader will start from third on the grid.
The added bonus for Verstappen is that Bottas pinched pole from Hamilton by just 0.096s with the second Q3 lap, while Mercedes has also decided to take engine penalties for the Finn with a power unit change that will be applied for Sunday's grand prix.
"I don't know where they [Red Bull] pulled out their pace," said Hamilton.
"They were miles off in [qualifying sessions] one and two but all of a sudden they were right up there with us, so it just shows it's super close."
Despite his performance, Hamilton claimed it was "not the best qualifyings from me", but declared himself happy for Bottas who will leave Mercedes at the end of the year for Alfa Romeo, with George Russell stepping in.
Hamilton added: "Congratulations to Valtteri, mega lap! It was looking pretty good from my side up until the end, just he went quicker and I couldn't match it, so well deserved.
"Q1 was really good for me, but for whatever reason, I then just struggled.
"Still, on the front row. It's great to have a front-row lockout for the team, that's great, particularly with the news last week, it's great to see Valtteri driving so well."
With three points for a sprint win, Hamilton knows it is crucial he claims the victory to close the three-point gap to Verstappen in the drivers' standings.
"We've lost a championship by one point, you know how that goes," said Hamilton, referring to his loss with McLaren in his debut year in 2007.
"There's been a lot of points lost this year on both sides, so every point counts, but these sprint races definitely can add and help so we have to try and capitalise on that."