Mercedes have been a great team, according to an elated Christian Horner. The Red Bull team principal praised his rivals as he celebrated Max Verstappen’s win at the Abu Dhabi Grand Prix.The Red Bull F1 team praised the Brackley-based team for pushing them to the limit through an intense season to bring out their best performances.Speaking to Sky Sports F1 after the race, Horner sang praises for Mercedes and said:"Mercedes are such a quality team and they have got stronger and stronger over the years. And that's what made this so intense on-track and off-track, the pit-crews, the strategies, the development between Toto and I. Because of the quality of the opposition we have had, that's what makes this one so special. You know we’ve just never given up from the first race."Formula 1@F1Congratulations @MercedesAMGF1, 2021 Constructors' ChampionsDisappointment in a phenomenal battle for the drivers' crown, but the Silver Arrows still make it 8 team titles in a row#AbuDhabiGP 🇦🇪 #F17:07 AM · Dec 12, 2021437485533Congratulations @MercedesAMGF1, 2021 Constructors' ChampionsDisappointment in a phenomenal battle for the drivers' crown, but the Silver Arrows still make it 8 team titles in a row#AbuDhabiGP 🇦🇪 #F1 https://t.co/u52KrHE7UhAccording to Horner, Mercedes' dominance is what pushed them to perform on-track and off-track, making Max Verstappen’s victory even more special. The Red Bull F1 team honcho, who has previously witnessed his team winning four titles with Sebastian Vettel, felt if it weren’t for his aggressive and precision-perfect rivals, this championship would not have shaped the way it did.Mercedes protest cloud looms over Max Verstappen’s celebrationsWhile Christian Horner sang praises for his rivals, Mercedes lodged protests against the race and their win. So until FIA stewards rule a decision, Max Verstappen is yet to be declared world champion after the Abu Dhabi Grand Prix.Formula 1@F1BREAKING: Mercedes have protested "against the classification established at the end of the Competition", relating to alleged breaches of Articles 48.8 and 48.12 of the FIA Sporting Regulations#AbuDhabiGP 🇦🇪 #F17:50 AM · Dec 12, 20216518611026BREAKING: Mercedes have protested "against the classification established at the end of the Competition", relating to alleged breaches of Articles 48.8 and 48.12 of the FIA Sporting Regulations#AbuDhabiGP 🇦🇪 #F1 https://t.co/bO6BLN8lv5The FIA has summoned representatives from both teams to argue their cases, and the race classification remains undeclared until then. While the constructors' championship has Mercedes sealing their eighth title, the drivers' championship is yet to be finalized. The provisional race classification remains as it stands, however, the final race classification is yet to be declared.