Perez lost the runner-up spot in the drivers' championship to Charles Leclerc on Sunday after floundering throughout the Italian weekend, as Red Bull struggled to find the right set-up for its RB20.
Perez is yet to beat Max Verstappen in qualifying or lead him on a single race lap this season, but his performance significantly deteriorated in Imola as he failed to reach Q3 – unlike both of sister team RB's cars – for the first time this season. On Sunday, he finished only eighth after a trip through the gravel, some 55 seconds adrift of his Red Bull team-mate.
Yet, Horner is not overly worried about this setback, calling it "just a blip".
"Our simulations were saying before the race that P7 was potentially optimal [assuming] nothing happened, no safety cars or anything like that," Horner said, with the race being run uninterrupted indeed.
"He had one trip through the gravel that cost him about six seconds, but I think that was about the maximum that he could get from that grid position today."
This below-par performance comes as Perez's future at Red Bull remains unsecured for the 2025 season.
Horner admitted the timing was unfortunate for his racer but was keen to point the bigger picture out: "It is a 24-race calendar. He has had a great start to the year, his approach has been very strong and he has changed his approach a bit this year. Today’s result was dictated by yesterday’s qualifying."
With both RB drivers Yuki Tsunoda and Daniel Ricciardo as well as Carlos Sainz – among others – vying for Perez's seat, Horner added that "we know exactly where we are at and what our options are. In the timing that is right for us we will make decisions about the future."
When asked how close Red Bull was to finalising the terms of a new contract with Perez and whether it was just a matter of signing, Horner made it clear that any potential deal wasn't just waiting to be signed: "Checo is always a very straightforward guy to deal with, so I wouldn’t expect that to be an issue."
