Though running in the wheel tracks of the Mercedes ahead, Piastri struggled to find a way through as the pair scrapped over fifth place through the middle of the 50-lap encounter on the Jeddah Corniche street circuit.
His path was only cleared when Hamilton finally pitted on Lap 36, releasing the McLaren which rose to fourth in the final classification.
While the battle was entertaining to watch, Piastri admitted it was less fun behind the wheel.
“I’m not sure fun is the word I would use; frustrating, yes,” the Australian said.
“It kind of just showed a couple of weaknesses of ours.
“I was very relieved when he boxed out of the way but, yeah, just didn’t quite have enough on the on the straights, mainly, to get past.”
While competitive through the highspeed opening sector of the lap, McLaren’s top speed was a weakness, and its DRS proved less efficient than others.
It meant Piastri only enjoyed a marginal benefit when he opened the rear flap, meaning drawing alongside early enough to make a move stick into Turn 1 was difficult.
That saw the 22-year-old attempt to get it done under brakes and twice skate through the run-off at Turn 1, handing the position back to Hamilton on both occasions.
Even when Hamilton began to struggle with tyre wear, the McLaren didn’t have enough in hand for Piastri to capitalise.
“It’s very, very even [between McLaren and Mercedes],” he reasoned.
“We have different strengths and weaknesses, for sure, and I think qualifying made the difference today.
“Lewis showed that if we qualified behind them, there was a good chance we were going to be stuck behind them for the whole night.
“So I think it’s very, very tight between us and we need to do some work to try and jump them and catch the two teams ahead.”
While Piastri was left frustrated having to spend almost half the race behind Hamilton, his team boss was more enthusiastic about the performance.
Having qualified fifth, the Australian moved forward a place at the expense of Fernando Alonso at the chequered flag, with both Mercedes – McLaren’s nearest rivals – behind him.
Andrea Stella was also pleased with how Piastri executed the race.
“Oscar’s race is effectively cashing in the strong results he already had yesterday, where he made strong progress through qualifying to qualify in P5,” the McLaren team principal reasoned.
“Today, he managed to gain one more position, finishing P4 in what I think was a very clean and solid race, staying out of trouble, being quick, but also being patient when you have to be patient – you don’t have to get nervous like “I’ve not been able to pass Hamilton, I’m going to attack even more’.
“Actually, at one stage, he had a little lock up into Corner 1. A couple of times when long… He stayed calm. He waited for the race to come to him. We’re just very, very pleased but not surprised.
“We see all the details, we see all the data, and we know the potential is very high. And we know that the consistency from a racing point of view, and mental point of view, is very strong.”
Across the garage, a strategy gamble with Lando Norris had the potential of netting a podium result, Stella claimed, had the cards fallen in his favour.
By leaving Norris on track under the Safety Car he gained track position but at the risk of having to pass on track later in the race once he pitted.
However, if there had been another interruption, he would have been in a position to gain handsomely.
“We knew that we could have lost a couple of positions, but with another Safety Car or with a red flag at the right time, and here it’s not necessarily such a remote eventuality and possibility, the race would have come to Lando with a big reward, like it would have been a podium finish,” Stella reasoned.
“So we thought it was worthwhile doing.
“Not an easy decision because effectively it could unfold like it did, so you lose a couple of positions, but very high potential in staying out. So we decided to go for it.”
After two rounds, McLaren sits third in the constructors’ championship with 28 points, two clear of Mercedes. Piastri is fifth in the drivers’ standings on 16 points.