The McLaren driver found himself locked in a fight for the final podium spot with Mercedes duo George Russell and Lewis Hamilton in the Montreal race but could not hold them back in the end as he came home fifth.
He reckoned that his hopes of a top three spot evaporated in the closing stages, when Russell and Hamilton clearly showed they aggressively wanted to move forward and passed him.
Asked how close he felt he had been to a podium, Piastri said: “Pretty close until I got behind the Mercedes, and then I realized that they were on a mission.
“It would have been, I think, incredibly tough to keep them behind all the way to the end - especially being sort of the first car in the firing line for them.
“I tried my best to stay in front, but I think just on the new tyres they were clearly a lot quicker than everybody.”
The step forward that Mercedes made in Canada has come as the result of a new front wing that first arrived on the W15 car at the Monaco Grand Prix.
But its full potential only became clear in Montreal when Mercedes was able to unleash some amazing pace at times – especially in practice and the early phases of qualifying.
Asked if he was surprised how quick Mercedes was, Piastri said: “I think the fact that they were fast wasn't a massive surprise. I think that they were so fast was.
“In FP3, I think with Lewis's [session topping] lap, we were scratching our heads. I think we worked out why after the session, but during the session, we were never going to get close to that. Even in Q2, when George did an 11.7 and I did a 12.1 or 12.2, I wasn't going to find half a second. So, I think they've been very quick this weekend.
“I think they've switched on the tyres well. And I think you kind of saw on the inters that that hurt them a little bit at certain points.
“So, yeah, it was maybe just a stronger weekend for them. But it wasn't totally unexpected. I think Monaco, they looked very strong at certain points. And yeah, I think this weekend, they've been very strong.”
Piastri did try valiantly to hold the Mercedes duo back and did get involved in a minor brush with Russell at the final chicane on lap 63 with a move that forced his British rival into the escape road.
Asked how he judged the incident, Piastri replied: “I need to see it a bit more. I think it's an incredibly tough corner to go two wide in. And, yeah, you need to be very brave to go around the outside.
“In the end he got past anyway. So, I don't think it really changed the result, but hopefully it was entertaining.”
