Piastri had qualified his McLaren second fastest before he was pinged for impeding Kevin Magnussen early in the qualifying hour – a mistake team boss Andrea Stella accepted the blame for.
That saw him start fifth, spending the opening stint of the race stuck behind Ferrari’s Carlos Sainz as a result.
It was decisive as, while he was able to clear the Spaniard courtesy of an undercut during the pit stop cycle, he was powerless to progress beyond Charles Leclerc in the other Ferrari around an Imola circuit that is notoriously difficult to pass on.
“Starting further back, I think that was the biggest thing today,” Piastri said of his race.
“I think the pace was honestly really good. I think in the first stint we were strong, just stuck behind Carlos.
“Then the second stint, pushed very hard at the start to undercut him and then also to try and get Leclerc.
“Just with the tyres, they just don’t like being pushed, so I just struggled a bit after that – looked like Charles had a very similar thing.”
Team-mate Lando Norris inherited Piastri’s second place on the grid courtesy of the Australian’s penalty, converting it into second in the race behind Max Verstappen.
It’s further confirmation, if any were needed, that McLaren is now a genuine contender for race wins.
Norris won the Miami Grand Prix after the papaya operation proved strong throughout the weekend. It was a similar case in Imola, where both Piastri and Norris were rapid all weekend.
Even prior to the upgades that debuted last time out, there were signs that McLaren had made progress.
“There’s a lot of positive things and encouragement to take for this week,” Piastri said.
“As a team, clearly we’re there.
“And I think personally, the last two weekends, I feel like I’ve been really strong as well.
“Miami felt like a really strong weekend here has felt really strong.
“That was the most we could have got out of the race,” he added of his fourth place.
“I’m very happy, feel like I’ve built a bit of good momentum in the last two weekends, which is something I’ve been trying to aim for a bit more.
“And I think as a team, we’re proving on different tracks, different conditions – which are generally conditions we’ve struggled in in the past – that we’re there in the fight for wins.”