Piastri was victorious over McLaren team-mate Lando Norris in Sunday’s race, becoming the fifth Australian to win in Formula 1.
The Melburnian celebrated in unique style; grabbing some Macca’s with team-mate Lando Norris and Williams driver Alex Albon.
A delay in his travel plans leaving Hungary following the race meant Piastri didn’t return home until the early hours of Monday morning, forgoing any lavish partying in Budapest.
“Celebrations are a work in progress,” Piastri told select media, including Speedcafe.
“Wasn’t the most glamorous of after parties. We had a flight back from Budapest that was significantly delayed and then flew into a different airport.
“I didn’t get home until about 5am, and my girlfriend was waiting at home for me.
“Spent with her the few hours that we were asleep, and that was about it.”
The journey home in itself was an ordeal, with the delay and limited food prompting an unusual dinner choice.
“Had McDonald’s – we were flying back with a few of the drivers, Lando was there, Alex Albon, a couple of others,” he revealed.
“In our wait for the delay, we got a cheeky Maccas, had a Big Mac, got home at 5am and that was the celebrations.
“Just a couple of F1 drivers, getting some burgers and nuggets, really,” he added.
“We didn’t take any trophies or anything, not that you can put anything in those trophies anyway.
“We had three or four hours of delays, and there wasn’t any food around, so McDonald’s was the nearest and most convenient thing, so that’s what we chose.”
Piastri won the Hungarian GP after McLaren employed team orders, moving Norris behind the Australian.
The Englishman had been given strategic priority to protect his second place from Lewis Hamilton at the final round of stops.
That left him artificially in the race lead in the closing stages, a point McLaren sought to address.
While Norris did eventually cede the place, he made the team sweat over it.
The situation was played down post-race, with Piastri confirming there was no awkwardness during their shared travel heading home.
“We were good,” he said of sharing McDonald’s with Norris.
“We were playing Monopoly on the way back on the plane. We’re all good, apart from Alex Albon teaching us a thing or two about Monopoly!”
Piastri’s win coincided with one of the few events manager Mark Webber has missed.
The nine-time grand prix winner was in London, supporting Mitch Evans in his quest to secure the Formula E World Championship.
Piastri’s girlfriend, Lily, also missed the event while his parents watched on from home in Melbourne.
“Of course it’s nice to have people that are close to you there. But it’s impossible to predict where you’re going to get good results, so it’s just luck of the draw of who’s there in some ways.
“Mark’s not missed many races in my F1 career, maybe three or four. He was very busy with Mitch in London, so don’t blame him at all for going to that.
“But I got to go see Lily that night, a little bit later than I’d planned, but it was nice to go back and see her.
“I had all the people at the track, I had the whole team, fans at the track saying well done.
“A lot of people that were in touch. It was nice, I still had people to spent it with – I had my physio Kim to spend it with and the whole team as well.
“That was very special and then I got to spend it with Lily as well, seen Mark today.
“It was very cool. Of course, if they could have been there at the race I’m sure it would have been even cooler but it was still nice to see them as quickly as I could.”
Formula 1 is back in action this weekend with the Belgian Grand Prix, the final event before the summer break.