Lando Norris went wheel to wheel with Lewis Hamilton early on at the Austrian Grand Prix but went on to finish P6 only one place behind his compatriot. Meanwhile, Sainz recovered from 19th on the grid after taking a penalty, to finish in eighth place. It was the second consecutive race both drivers had placed in the top ten.
Both drivers are in their first season with McLaren with this being Norris' first season in the pinnacle of motorsport. Following the race at the Red Bull Ring Seidl praised the pair and looked to the future.
"I'm very happy with both drivers and they will be the future of this team," Seidl said as quoted by Sky Sports.
Seidl also singled out Norris for his raw pace and highlighted his consistency, adding: "The most important thing is raw speed, that is the base for every successful driver. He has shown from the first race onwards that he had this speed.
"If you go in your first-ever F1 qualifying [in Australia] and you go to Q3 straight away and score P8, and then do it more and more often, so it was not just a one-off."