The Red Bull team principal was speaking with the British media outlet having seen his drivers struggle for pace in the first two sessions of the weekend.
His star driver Max Verstappen has won the three races at Zandvoort since the Dutch Grand Prix was revived in 2021, but bemoaned the lack of pace in his RB20 on Friday.
His team-mate Sergio Perez, was - as he has been virtually all season - further behind still, and the subject of Horner's defensive interview.
Christian Horner is team principal at Red Bull RacingSergio Perez has been in dire form in 2024, though still retained his seat
What does Christian Horner think about Sergio Perez?
Perez's form has been the subject of permanent discussion in 2024. After four podiums in the first five races, the Mexican's form has fallen off, failing to even finish in the top six since round six in Miami.
Red Bull coasted to consecutive constructors' championships in 2022 and 2023 such was their pace advantage, whereas in 2024, Perez's shortcomings have allowed McLaren, Ferrari, and Mercedes to significantly close the gap.
Rumours before the summer break indicated that the 34-year-old could be replaced, but Horner shut down those reports by confirming Perez would stay for at least the remainder of the season.
In his chat with Sky, Horner emphasised how Red Bull needed both cars fighting at the front to help their championship bids, which prompted Pinkham to question why Perez was kept on, given that he had not been offering Verstappen much support against rivals.
"Well, who would you put in?" Horner immediately replied, to which Pinkham argued that she was not the Red Bull boss and that it was not her decision.
"Well, you ask all the questions," retorted Horner.
Natalie Pinkham (right) is a regular host and pundit for Sky Sports F1
Pinkham tried a different avenue to probe the team principal, and asked whether Red Bull retained Perez because there was not a suitable replacement available.
"No, look, I think that we know what Checo [Perez] is capable of. We know that at the beginning of the year, you know, he was scoring - what, four podiums in five races?
"If we can get him back into it. I think he's just had, you know, a lack of confidence. And has ended up in a bit of a spiral. I think he's had a bit of a reset, hopefully, over the summer break.
"We know that there's tracks that he's won at coming up. We've got Azerbaijan, where he's won both sprint race and grand prix on the same weekend. He's won another fantastic race in Singapore against Charles Leclerc in mixed conditions. He's been very quick at Monza.
"This Zandvoort hasn't been his best circuit. So of the four races coming up before the next mini break, I would say this is his most challenging one."
In one final challenging question, Pinkham queried whether it was 'crucial' for Red Bull to keep Perez until his home race, the Mexican Grand Prix. The driver brings in sizeable sponsorship money from his North American home country.
Horner was adamant that was not the reason, though: "No, no, absolutely not. It's all about performance. So, you know, for us, we've got the two drivers that we believe in our pool of drivers are the most capable of giving us the best results.
"If there was a doubt in that, then we would have changed it."
With Perez stated to keep his seat until the end of the season, he will need to improve his performances if Red Bull are to retain the constructors' championship.
GP AUSTRALIA
22 - 24 Mar
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5 - 7 Apr
GP CHINA
19 - 21 Apr
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3 - 5 May
GP ITALY
17 - 19 May
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24 - 26 May
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26 - 28 Jul
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13 - 15 Sep
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25 - 27 Oct
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1 - 3 Nov
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