Piastri qualified fifth fastest for the Marina Bay race after a mistake on his final flying lap in Saturday’s qualifying session.
In the race itself, it left the rapid McLaren stuck behind the Mercedes duo of Lewis Hamilton and George Russell for the opening stint.
That delay proved costly, and likely the difference between second and third on the podium.
“[Qualifying] obviously wasn’t ideal, but today the aim was to get onto the podium,” Piastri said.
“I think losing so much time behind the Mercedes in the first stint meant that that [third] was definitely the most we could have done, so walking away reasonably happy.
“I think it was a good damage limitation day today.”
Piastri started the race on the medium tyre, stretching his opening stint to Lap 38 before switching onto the hards for the run home.
It was a strategy that gave him a healthy tyre advantage over the two Mercedes, allowing him to catch and pass the pair to claim the final podium place.
“It was difficult for the last few laps of the stint, but until then I could tell that we had a good pace advantage over Mercedes,” Piastri explained.
“And Lewis starting on the soft meant that I was never really going to try and push to get him early on.
“I knew that the race was going to come to me much later on, and that’s basically what we did.
“When I was in the dirty air behind them, it was tough, as it always is, but I knew that we had a good pace advantage and that the longer we kept going the more opportunities we opened up for ourselves the bigger tyre difference we had.
“If there was a Safety Car then we could have capitalised on it, so I think we executed it very well.”
Piastri cleared Hamilton at Turn 7 on Lap 40, and Russell at the same corner five laps later.
With stronger pace than the Mercedes duo, but a sizeable gap to Max Verstappen ahead, it made for a lonely run to the chequered flag.
“It almost gets harder when it gets lonely,” he said in reference to racing in the hot conditions in Singapore.
“Once I got past the Mercedes, Max was, I think, 20 seconds ahead, and I knew I was a lot quicker than the Mercedes, so the last 15 laps felt longer than the first 45.
“It was a tough race, definitely. It always is here.
“In some ways having the air blowing in your face and stuff like that is almost quite nice.
“The in-lap was actually probably… when you stop concentrating so much and you don’t have as much air in your face, it actually can feel worse.
“Definitely a tough evening, but that’s what we’re paid for.”