Norris and Piastri finished third and fourth behind Ferrari duo Carlos Sainz and Charles Leclerc in Melbourne after McLaren asked Piastri before halfway to swap positions with Norris.
But while the Australian rued missing out on a podium in front of his home crowd, he conceded the swap was fair because had been allowed to undercut his team-mate earlier in the race, and thereafter Norris was faster on fresher tyres.
"For me, it was completely fair," Piastri said. "He qualified in front of me yesterday, went a bit longer on the first stop and he was catching me and was quicker at that point of the race.
"At that point, I was keeping with Leclerc and Lando was catching both of us, so I was honestly kind of hoping he'd be past me and go and get Charles.
"Of course, at home, I would have loved to be able to stay in third. But for me, that was completely fair."
Norris duly distanced Piastri and closed in on Leclerc, but didn't have enough in the bank to challenge the Ferrari, saying getting undercut in the first round of pitstops is where he lost a chance at finishing second.
Source: Autosport