The 2021 F1 season introduced "Sprint Qualifying" (hereby abbreviated as "SQ") in some races as an experimental event during the race weekends (i.e. Monza and Brazil GP). SQ is held on Saturday.
In SQ, drivers race in the same format as the main race on Sunday, but with the total distance shortened to about a third (100km). The starting grid of SQ is determined by the Qualifying event, which happens earlier than ordinary, on Friday.
This article on F1.com had pretty much explained the new format. I read it and understood that, the SQ adds points to the championship points of the top 3 finishers. However the article doesn't say exactly how the result of SQ would affect the starting grid on Sunday race:
The finishing order of the race will define the grid for Sunday’s showpiece event – the Grand Prix, where the traditional format remains unchanged. [Emphasis mine]
So, how would SQ affect the starting grid of the Sunday's main event? For example, if a driver qualified P8 after the Friday's Qualifying event and finished P1 after the SQ, what would be his starting position on the Sunday race? (Provide he doesn't have any grid penalties and neither do the driver in front of him, from P1 to P7.)