Saudi Pro League (SPL) clubs splashed $957 million on players during the transfer window, Deloitte said in its report on Friday.
The Gulf state’s spend in the transfer window, which closed on September 7, exceeded four of Europe's 'big five' leagues with only the Premier League ahead of the Middle Eastern nation.
"This marks the first time since 2016 that another international league has outspent any of Europe's 'big five' during a football transfer window...," said Izzy Wray of Deloitte's Sports Business Group.
"European football continues to be the benchmark for the game globally, and the Saudi investment in the game will divert its focus towards the infrastructure, to elevate the level of Asian football."
Earlier this year, the Saudi Public Investment Fund (PIF) announced a Sports Clubs Investment and Privatization Project involving the league champions Al-Ittihad, Al-Ahli, Al-Nassr and Al-Hilal, with a host of top players moving to the league.
PIF own 75% of each of the four clubs, while their respective non-profit foundations own 25% of each.
This window's biggest transfer move came from the most successful club in Saudi Arabia, Al-Hilal, who spent 90 million euros to bring in Brazil star Neymar from Paris St Germain.
In addition to Neymar, Al-Hilal also spent big money to sign Aleksandar Mitrovic, Kalidou Koulibaly, Ruben Neves and Sergej Milinkovic-Savic.
Saudi Pro League champions Al-Ittihad signed Karim Benzema, N'Golo Kante and Fabinho, while Cristiano Ronaldo's Al-Nassr splashed out on Otavio, Sadio Mane, Aymeric Laporte, Marcelo Brozovic and Alex Telles.
Al-Ahli, who returned to the Pro League following a season in the second division, also completed a string of signings including Gabri Veiga, Riyad Mahrez, Roberto Firmino, Edouard Mendy, Alain Saint-Maximin and Merih Demiral.
"The implementation of the Kingdom's privatization program is likely to draw a wave of interest around the SPL, potentially fueling the current spending pattern for the windows to come," Wray said.
"With the spending power of the SPL already surpassing some of Europe's 'big five', it remains to be seen the impact this will have on the make-up of elite football for future generations."
For all its expenditure, the SPL still missed out on some of its biggest targets.
Liverpool's Mohamed Salah was a target for Al-Ittihad, who reportedly had a bid worth 150 million pounds ($187.10 million) turned down by the Premier League club, while ambitious bids from Al-Hilal for Lionel Messi and Kylian Mbappe failed to materialise.
Saudi Arabia has made massive investments in soccer, Formula One, boxing, tennis and golf in recent years.
Critics accuse Saudi Arabia of using the PIF to engage in "sportswashing" in the face of heavy criticism of the country's human rights record.
— Additional input from Reuters