Norris trailed McLaren team-mate Piastri following a poor getaway from pole position, but an earlier second pit-stop propelled him into the lead.
But Norris was then ordered to concede first position to Piastri, allowing the 23-year-old Melbourne driver to claim his first win.
Here are the Norris exchanges in full.
Piastri race engineer Tom Stallard: "OK, Oscar, once you get to Lando, we will swap positions, but we want to avoid Lando having to give up a lot of race time."
McLaren race engineer Will Joseph to Norris: "We need you to save more tyres please. And let Oscar through."
***
Joseph: "OK, Lando, we still think you are using the tyres too much. In Turn 4, Turn 11 and the rears at exits Turn 6, Turn 9. Oscar is 3.5 (seconds behind). I know you will do the right thing."
***
"OK, Lando, 10 laps to go and we think both cars are using their tyres too much. Just remember every single Sunday morning meeting we have."
Norris: "Yeah, well tell him to catch up then please."
Joseph: "Lando, he can't catch up. You have proved your point and it really doesn't matter."
Norris: "He is on much quicker tyres and no pressure. I would have tried the undercut anyway."
Joseph: "Mate we did the pit stops in this sequence for the good of the team."
Norris: "And I am fighting for a world championship, am I not?"
Joseph: "I am trying to protect you, mate. I promise, I am trying to protect you."
***
Joseph: "Ok, Lando there are five laps to go and the way to win a world championship is not by yourself. It is with the team and you are going to need Oscar and you are going to need the team."
***
Joseph: "If there is a safety car, this is going to make it very awkward. Please do it now."
(Norris moves aside to let Piastri take the lead)
Norris: "You don't need to say anything."
