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 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."
Sainz says Ferrari nailed the many strategy calls the team had to make, an area of the team that has come under fire in recent years.
"Honestly, today we nailed the calls, except for the first stop that we should have boxed on the first lap and we stayed out one extra lap. Everything else, we nailed it.
"And even the pace at the beginning of the race on new intermediates was really good, and as the race settled down in mixed conditions I was quick, but when the race settled down, we were just not back to our normal pace.
"But a lot of attacking, a lot of defending, had fun out there, but the reality is that once the race settled we were nowhere."
Team boss Fred Vasseur explained that Ferrari had opted for a lower downforce set-up, a choice which ultimately didn't pay off in the difficult mixed weather conditions the North Sea sent Zandvoort's way.
"For sure we were on the low side of the downforce and the conditions didn’t help us," he said.
"It’s clear that our package would have been better in standard conditions and more consistent conditions, but it’s not an excuse at all.
"We were already a bit too much up and down. If you have a look at what Charles [Leclerc] did yesterday, I think the pace was very good at this stage before the crash [in Q3].
"But it’s not the result that we are expecting overall."
While Sainz held on to finish fifth, Leclerc retired from the race as the result of floor damage he sustained in contact with McLaren's Oscar Piastri on lap one, which he said cost him 60 points of downforce.
Additional reporting by Kevin Scheuren
