The Spaniard equalled his best result of the season with fourth place at the Red Bull Ring while his team-mate Charles Leclerc finished runner-up to dominant victor Max Verstappen.
Sainz had pressured Leclerc for second during the opening stint, but it was agreed that the Ferrari duo would not fight for position.
This pre-race order would come to leave Sainz vulnerable during an early virtual safety that "compromised" his race and cost what he thought to be three places.
By not having track position, Sainz was held behind Leclerc for a delayed Ferrari double-stack pitstop, which meant he was still being serviced when the VSC ended to cancel out some of the advantage.
Sainz explained: "I was very quick on the first and second stint. Obviously, the second stint was already compromised by the first stop, pitting behind Charles and catching the virtual safety car ending, which made me lose six/seven seconds of race time.
"It made me lose positions to cars that I shouldn't have lost, which meant then I had to push on the medium [tyre] to overtake them, get the track limits [penalty].
"My race was compromised from that point onwards. But if I look at the pace, I was very quick out there."
Source: Autosport