Valtteri Bottas will start Saturday's sprint race from pole position but will be at the back of the grid for Sunday's Italian Grand Prix.
Mercedes changed engine, turbocharger, MGU-H and MGU-K on Bottas' car, all outside the allowed component allowance for each part. That automatically leads to a grid penalty.
Shortly after Mercedes confirmed the change, Bottas claimed the quickest time in Friday evening's qualifying session.
Like the British Grand Prix in July, Monza's schedule has been shuffled around to accommodate a sprint qualifying race on Saturday afternoon.
The result of that shortened race will set the grid and officially crown a driver with pole position.
As a quirk of those new regulations, Bottas will start the sprint race from pole position but then serve the penalty ahead of Sunday's race. It means Bottas and Mercedes can still aim to score the points on offer for finishing Saturday's race in the top three positions.
Bottas, who earlier this week was confirmed to be joining Alfa Romeo in 2022, said he will push tomorrow ahead of the grid penalty.
"It feels so good when you get a nice lap," Bottas said.
"I managed to save it until the end and had a bit of a tow finally, so it was good fun. I enjoyed it. As you said, I feel good, I feel relaxed, and everything is sorted for the future and obviously really pleased with the Team today.
"The car has been so good and obviously further on next year there will be new exciting things for me and I'm looking forward to it, but for now focus is for tomorrow's sprint race. Of course, starting from the front, expecting to get the maximum points tomorrow and then do the best job we can on Sunday.
"The weekend started nicely and I'm happy."