Tsunoda was on course for his best result of the year in Mexico when he attempted to overtake Piastri’s McLaren into Turn 1.
In similar fashion to Sergio Perez on the opening lap, Tsunoda slightly misjudged his turning point.
The contact spun Tsunoda out of the points, while Piastri continued with some minor damage.
Tsunoda wasn’t surprised the stewards didn’t hand Piastri a penalty because “they love the top teams”.
“They love top teams so that’s it,” he said after the race.
“The car pace was as good as we expected. I mean, we showed a good performance on Saturday, so it’s a shame that I ended up like that.”
On the other side of the AlphaTauri garage, Daniel Ricciardo finished seventh, which moved them ahead of Alfa Romeo and Haas in the constructors’ championship.
Tsunoda will have the chance to make amends at this weekend’s Sao Paulo Grand Prix.