In a mixed weather race, Sainz admitted Ferrari "was nowhere" on pace and says both he and the team executed a near perfect race to finish fifth, holding off Mercedes' Lewis Hamilton and McLaren's Lando Norris at the chequered flag.
"I would say after looking at the Alpine [we were] more [like] the sixth-fastest car this weekend," said Sainz.
"I know at some point it looked that we even could fight for a podium but the reality is that when the race was settled when you look at our pace we were just nowhere.
"But we managed to execute a really good race, we were fighting the whole race with people that were not in our pace, not in our race, fighting a lot quicker cars than us.
"So, we have to be happy and proud of a well-executed P5. Obviously not happy with the feeling of the car and how much I struggled out there today.
"It has to be one of my best drives of the season, for sure."
Source: Autosport