With the financial ramifications of the COVID-19 pandemic beginning to ease off, a lot of clubs conducted shrewd business in the 2021 summer transfer window.While loan deals remained the preferred mode of business for clubs, there were also some notable transfers this summer. Lionel Messi and Cristiano Ronaldo - arguably the two best players to have graced the game - moved clubs, albeit for different reasons.Ronaldo returned to his old stomping ground at Old Trafford, while Messi joined PSG after Barcelona failed to renew his contract. The summer also saw Manchester City and Chelsea splurge in excess of €100 million to land Jack Grealish and Romelu Lukaku, respectively. Most of the other top six clubs in the Premier League have also made significant changes to their rosters.Elsewhere, Atletico Madrid acquired Copa America 2021 winner Rodrigo de Paul. Bayern Munich brought in Dayot Upamecano and Marcel Sabitzer from their Bundesliga rivals RB Leipzig. Real Madrid landed exciting teenage midfielder Eduardo Camavinga after failing to land their primary target, Kylian Mbappe. Barcelona and PSG also made a spate of high-profile free transfers.On that note, here's a look at the 10 most expensively assembled teams in club football at the moment:NOTE: All figures are courtesy transfermarkt.#10 Barcelona - €696 millionMemphis Depay has made a fine start to life at Barcelona.Barcelona have largely been in the news this summer for one reason - the exit of their club legend Lionel Messi.The Blaugrana - who have one of the biggest wage bills of any club - couldn't offer their talisman a new contract owing to La Liga's financial fair-play rules. However, Barcelona did acquire Memphis Depay (valued at €45 million), Sergio Aguero (€18 million) and Eric Garcia (€20 million) on free transfers. Depay has made a good start to life at Camp Nou, scoring twice in three games.3 - Memphis Depay 🇳🇱 has become the first @FCBarcelona player to be involved in a goal in each of his first three appearances in @LaLigaEN (two goals and one assist) since Cesc Fàbregas 🇪🇸 in 2011 (three goals and four assists). Stellar. pic.twitter.com/Z9OUsUPSz1— OptaJose (@OptaJose) August 29, 2021Despite Messi's exit, Barcelona have a promising roster. They are led by their most expensive player, Frenkie de Jong (€90 million) and the prodigious Pedri (€80 million). Goalkeeper Marc Andre Ter Stegen and La Masia graduate Ansu Fati, set to return to action after a year, are both valued at €60 million.Meanwhile, two of Barcelona's most expensive flops, Ousmane Dembele (€50 million) and Philippe Coutinho (€30 million), are the other most valuable players on their roster.#9 Tottenham Hotspur - €697 millionTottenham Hotspur are leading the 2021-22 Premier League.With a squad value of close to €700 million, Tottenham Hotspur are the ninth-most expensive team in club football at the moment.The 2021-22 Premier League leaders may have spent €67 million to land Bryan Gil, Emerson Royal and Pape Sarr. But arguably their biggest 'win' this summer was keeping hold of their prolific scorer Harry Kane, who is valued at €120 million.Although the England international is yet to open his account this season, his striker partner Son Heung-Min has been on song. The €85-million-rated South Korean has scored two game-winners for the unexpected league leaders, including one against holders Manchester City.1 - For the first time in top-flight history, Tottenham Hotspur will end the day top at the same time as Arsenal ending the day bottom of the table. Parallel. pic.twitter.com/Z926RdCCMa— OptaJoe (@OptaJoe) August 29, 2021Other valuable personnel on the Spurs' roster include the injured Tanguy Ndombele (€50 million), Pierre-Emile Hojbjerg (€40 million) and their on-loan centre-back Cristian Romero (€35 million). Their captain Hugo Lloris may be valued at only €9 million, but the 34-year-old is yet to concede in three games this season.#8 Atletico Madrid - €755.2 millionAtletico de Madrid could be the team to beat once again in the La Liga this season.Atletico Madrid haven't made too many changes to their roster this summer. Frenchman Antoine Griezmann has returned to the Wanda Metropolitano, while Rodrigo De Paul has arrived from Serie A.That could make the holders the team to beat in La Liga once again, as they have a decent mix of youth and experience. They have quality and depth in every department of their roster.Antoine Griezmann back to Atletico Madrid, HERE WE GO! Agreement now completed with Barcelona. Loan until June 2022 with buy option for €40m. ⚪️🔴 #Atleti #DeadlineDayGriezmann has agreement for two years contract plus one option. He’s BACK at Atléti. Shocking move of the day. pic.twitter.com/kBQAkgQyLt— Fabrizio Romano (@FabrizioRomano) August 31, 2021In Jan Oblak (€70 million), Atletico Madrid have arguably the best custodian in La Liga, and probably in all of Europe. Jose Gimenez (€80 million) and Stefan Savic (€30 million) form an experienced duo at the back. The Rojiblancos also have experienced campaigners like Marcos Llorente (€80 million), Koke (€80 million), Yannik Carrasco (€40 million) and now De Paul.Up front, Atletico have the 21-year-old exciting Joao Felix to complement Luis Suarez (€15 million) and the returning Griezmann (€80 million).#7 Real Madrid - €783.5 millionReal Madrid are in rebuilding mode right now.Real Madrid lost their former manager Zinedine Zidane at the start of this summer. Following the Frenchman's exit, Los Blancos also saw their two defensive mainstays, Sergio Ramos and Raphael Varane, leave the club this summer. The club managed to sign David Alaba on a free transfer, but the versatile defender is unlikely to play in the center of defense.Real Madrid did bring in the exciting Eduardo Camavinga to bolster their aging midfield. But the Merengues failed in their pursuit of PSG star Kylian Mbappe, despite submitting a gargantuan offer. Add to that the trio of Karim Benzema, Luka Modric and Toni Kroos being on the wrong side of 30, Madrid could be in for a difficult campaign.Eduardo Camavinga has just signed his contract as new Real Madrid player. Paperworks between Real and Rennes were already signed in the night for €31m plus add ons. Here-we-go confirmed. ⚪️🇫🇷 #RealMadrid #DeadlineDay— Fabrizio Romano (@FabrizioRomano) August 31, 2021There is no doubt that Madrid have a plethora of experience, starting with their most valuable player Casemiro (€70 million). The defensive midfielder is regarded as one of the best in the world in his position. The same also goes for their custodian Thibault Courtois (€60 million) and Alaba (€55 million).Meanwhile, the teenager Camavinga is also valued at €55 million, while 23-year-old midfielder Fede Valverde is worth €65 million. Left-back Ferland Mendy is the fifth Madrid player with a valuation of at least €50 million. However, the likes of Gareth Bale (€18 million), Dani Carvajal (€30 million) and Isco (€18 million) have seen their valuations drop.