Ever since Pep Guardiola's arrival in the Premier League, Manchester City have been a formidable club on the domestic and continental stage. At the onset, Guardiola was promised freedom and financial backing to bring to life his vision of "total football." It represented his famed purist approach to the game.Adapting the squad to his playing style and vision took a season, but since then, the Sky Blues have won three league titles, an FA Cup and four League Cups on his watch. Since his arrival around the time of Jack Grealish's signing for £100m in the summer of 2021, Pep Guardiola has spent over £918m on players in five years. With that in mind, we rank the five best signings overseen by Pep Guardiola during his spell at Manchester City:#5 Ruben DiasManchester City v Everton - Premier LeagueRuben Dias' signing in the 2020 transfer window was a transformative arrival akin to Liverpool's signing of Virgil van Dijk. Signed from Benfica for a hefty fee of over £60m, he was part of the tightest defense in the Premier League. Dias helped transform an error-prone backline into one of the league's very best. His height and immaculate sense of positioning has taken many by surprise,Rúben Dias' stats for Manchester City:✅44 games⛔️24 clean sheets⚽️20 goals conceded23 years of age. The Portuguese Wall. 68M well spent. 🔵🇵🇹 pic.twitter.com/Au5mvl1zKk— FootyEmporium (@EmporiumFooty) April 26, 2021His presence has undoubtedly brought out the best in a rejuvenated John Stones. They complement each other's game much like Rio Ferdinand and Nemanja Vidic's pairing from yesteryear. Still only 24, Dias is set to be a Manchester City mainstay for years to come.#4 Kyle WalkerManchester City v Chelsea FC - UEFA Champions League FinalKyle Walker was identified as a tactically adept player for Pep Guardiola's defensive system. Subsequently, he was bought from Tottenham Hotspur for a highly scaled-up fee of £50m.Since his move to the Etihad, Walker has firmly established himself as a dependable fullback, vital to circulating possession and stopping counterattacks with his rapid pace.As an "inverted fullback" stepping into midfield, Walker has revolutionized the fullback position and acts as an auxiliary midfielder - a one-of-a-kind position. He's been present for a large part of Manchester City's success under Guardiola and is sure to be a mainstay with the Cityzens over the next few years.