Manchester City have made further reinforcements to their already world-class squad by adding both Erling Haaland and Kalvin Phillips in this window. While Haaland, who arrived from Borussia Dortmund amid much speculation and fanfare, will get the headlines, some may argue that the signing of Phillips from Leeds United is just as important for manager Pep Guardiola and Manchester City.In this piece, we will be looking at the tactical importance of Phillip's signing and how the Yorkshire-born midfielder fits into Guardiola's complex system.Kalvin Phillips suits Manchester City's style of playOne of the most important bits of business in this transfer window was for Manchester City to replace their departing captain and defensive midfielder, Fernandinho. Phillips is a rare kind as he is already suited to the style of play due to his development under former Leeds manager Marcelo Bielsa playing as a single pivot defensive midfielder.Leeds United@LUFC🤍 Thank you, @Kalvinphillips!286902051🤍 Thank you, @Kalvinphillips! https://t.co/X6ls9vDpBdThe midfield in a Guardiola team depends on energy and workrate, which you can see in the likes of Bernardo Silva, who topped the most distance-covered stats last season. Phillips' workrate near enough matches Silva's, despite playing in a deeper role. Fernandinho's energy has been key for Manchester City for years, so finding a replacement that is not only is technically gifted but also with the workrate to match was important for City.Kalvin Phillips@KalvinphillipsSo proud to join one of the best clubs in the world. Can’t wait to keep on challenging myself and learn from the best along the way 🏽 @ManCity1143669685So proud to join one of the best clubs in the world. Can’t wait to keep on challenging myself and learn from the best along the way 🙌🏽💙 @ManCity https://t.co/FKPr2XYRdSPhillips is admired for his rise through the EFL Championship with Leeds and subsequent impressive displays at both domestic and international level. Many consider the Leeds academy graduate to be one of the best at reading the game, which is important when coupled with his range of impressive passes.Mancehster City may look to deploy a double pivot next season in big games, much like they did last season. The double pivot normally consisted of Ilkay Gundogan and Rodri last term, which allowed Kevin De Bruyne to play higher up and contribute in the attacking third of the pitch.Manchester City@ManCityWe are delighted to announce the signing of @Kalvinphillips on a six-year deal 🤩Welcome, Kalvin! #ManCity503088970We are delighted to announce the signing of @Kalvinphillips on a six-year deal 🤩Welcome, Kalvin! 💙#ManCity https://t.co/3fNJthPNILOne for the futureNot only is this a signing for the present, it is also a signing for the future. Phillips signed a six-year deal showing the Manchester club's trust in him. While he may not come straight into the starting XI, with Gundogan's contract expiring, he may have a key role to play in the coming seasons. The midfielder is also just 26 years old and has plenty of time to adapt and improve his game.The £42 million fee for the England international may have seemed steep at the time of the signing, but we could well be looking back at this deal in two or three years as a shrewd signing.