Perez, who himself became the first Mexican to finish on the podium in a world championship event since Pedro Rodriguez at Zandvoort in 1971, said winning was possible, and hailed the team for its great job during a difficult event.
"I think the win today was really possible," said Perez, who is fifth in the championship with 22 points. "Obviously the team did very good work to call me in at the right time. We lost just [time] at the end a lot of second pitstop, which did not go well with the clutch, but then I managed to catch him [Alonso] lap by lap.
"I lost control of the car and lost the fight for the victory. Even so, it has been a great day for the team. They called me at the right time. The conditions were difficult to keep the car on track, and it has been incredible. They were focused as well, calling me at the right time, which was crucial."
Perez caught up with Alonso after a slow second pitstop, but slid wide when he looked set to attempt a pass on the Spaniard.
"I knew I had to be quick to overtake him as I had a lot of degradation in the tyres," he said. "I was looking for a way to get him and then I ran a bit wide and touched the wet kerb and was lucky to not go off.
"In the end second place is a great result for the team. It's many points. It's only the second the race, but hopefully we can keep improving to fight."