Before heading the Red Bull F1 team, Christian Horner aimed to become an F1 driver himself. However, the Briton joined F1 in 1998, but former IndyCar champion Juan Pablo Montoya's speed gave him a reality check in the pre-season testing at Estoril, Portugal.Montoya is regarded as one of the most revered drivers from Colombia to grace the motorsport sphere. His precision and excellence behind the wheel of a racecar helped him win races in the premier open-racing series in the United States, and later went on to bag the elusive title in 1999.However, before this, Montoya used to race in the junior racing divisions and was a rival to Christian Horner in the latter's racing days. In 1997, the Colombian had missed out on the title by less than two points and was looking for his redemption in 1998.With no space for errors, Montoya had a clear determination in his mind, which could be seen at the pre-season testing at Estoril Circuit in Portugal. Horner got the first-hand experience of Montoya's racing calibre and shared how he decided to back out of his racing ambitions after witnessing the risk involved in being a valued competitor.In 2021, Horner said on the High Performance podcast:"Even before the season had started. At the beginning of 1998, was when I drove out the pitlane, in Portugal, and there used to be a really high speed turn. That was, so one downshift, straight into the corner and there's barriers that are about three meters from the edge of the track."And Juan Pablo Montoya coming past me as I was coming out of the pitlane, into this corner and I could just see the angle that this car was at, the commitment that he had. And he was just absolutely planted. I thought, 'I can't do that.' My foot and brain are saying, "don't do it.""In reality, I just knew that I haven't got the ability to disconnect the risk, versus the, reward that it had... And seeing his commitment, that was an eye opener to me, to think, 'you're not capable of doing that.'" View this post on Instagram Instagram PostThis led Horner to back out from racing altogether after the conclusion of the 1998 International Formula 3000 championship, where he finished 33rd in comparison to Montoya's first.How did Juan Pablo Montoya and Christian Horner's careers pan out in the following decades?Juan Pablo Montoya (L) and Christian Horner (R) at the 2024 F1 Grand Prix of Abu Dhabi - Source: GettyWhile Juan Pablo Montoya continued his racing venture and joined the IndyCar grid in 1999, Christian Horner moved over to the operational side of racing. The 49-year-old had become an IndyCar champion in his rookie year while sharing glimpses of Nigel Mansell's 1993 championship campaign.On the other hand, Horner became the team principal of Red Bull in 2005, as the Austrian energy drink maker bought the Jaguar outfit. This made him in charge of the Milton Keynes-based squad, which under his leadership won six Constructors' and eight Drivers' titles.However, this successful partnership ultimately came to an end a few weeks earlier, as the Austrian giant sacked Christian Horner from the team with immediate effect. Also, no hints have been provided on where the Briton could head next, or whether he is bidding farewell to the sport.