Seidl also praised the Spaniard for the way he has dealt with the potentially awkward transition period as he races for McLaren while being committed elsewhere for the future.
Sainz currently lies seventh in the World Championship after charging from 15th on the grid to fifth in Istanbul last weekend.
“A race like [Turkey] just confirmed the quality Carlos has,” said Seidl. “We know from previous races in the last years that he likes all of these tricky conditions, he likes these wet or mixed conditions, we know that he is performing well in these conditions, and that he has this talent to take the right approach in terms of risk.
“And he manages to keep the car on track while still making progress on track, and making the moves stick like he did today. And it’s simply a big benefit.
“Also [it helps] if you have a driver that works for some time already with his engineer, and his engineering team, because in conditions like today, you have a lot of communication ongoing between driver and the pit wall.
“And there you see also the experience Carlos has, because it’s important then to stay brief on the radio, calm but also clear of what’s going on out there at the track, so that we can match this with the data we see on the pit wall, and that in the end makes them make the right decisions at the right time.
“He’s a great driver. There’s a reason why Ferrari went after him for next year.”
Regarding Sainz’s off-track contribution Seidl added: “I really like also the approach, how he deals with the situation, together with us, fully committed, very motivational for the entire team.
“And that’s key I think also for the results we are getting together with him at the moment.
“So I’m really looking forward to the last three races with him in our team, and then hopefully we beat him next year!”
Seidl also praised Lando Norris for his recovery in Turkey from last place off the grid to eighth at the end.
“On Lando’s side, seeing the pace he could show in the race it was obviously disappointing that he was pretty much last after the start,” he said.
“I think he had an anti-stall on the grid, because it was simply so difficult to launch a car from these low grip conditions. He was unfortunately on the bad side of the grid.
“So that obviously compromised then the rest of his race, but also there, with the performance he has shown, I’m very happy.
“It confirmed again, also, the quality Lando has, especially in these tricky conditions. And it was great to see how he recovered from last position to P8.”