And the suddenly, with credibility at least partly restored, sponsors and investment returned in a big way, along with the sport’s disillusioned fans.

Guangzhou’s club experienced perhaps the biggest turnaround: Relegated to China’s second division in 2010 as punishment after allegations of match fixing, the team was bought by a big-spending real estate group, Evergrande, and it signed Italy’s World Cup-winning coach, Marcello Lippi, and the high-priced foreign players like Argentine Dario Conca. Three years later, it became the first Chinese team to win the Asian Champions League trophy.

Last year, the team got another boost when the Chinese online sales behemoth Alibaba purchased a 50 percent stake for $192 million. It also announced it would set up soccer academies for young Chinese players in Spain and the Netherlands.

Now every team in the league wants to replicate the Evergrande model. According to FIFA, during the recent winter transfer window, Chinese Super League clubs spent a record $85.5 million on foreign players — the third-highest total in the world and more than five times what they spent in 2013.

Evergrande was again the biggest spender, paying a C.S.L.-record $16.2 million for the Brazilian Ricardo Goulart, but other clubs also made flashy deals, most notably Shanghai SIPG, which signed Conca for a reported $10.8 million per year and hired the former England manager Sven-Goran Eriksson as coach.

Conca’s salary has not been confirmed by his club, but if it is accurate, it would be similar to the salaries received by Cristiano Ronaldo and Lionel Messi.

“Suddenly, everyone buys top foreigners,” said Mads Davidsen, a Danish assistant coach at Shanghai SIPG who has been in China since 2013. “When I came here, the foreigners on C.S.L. teams didn’t have that good a level. Now it’s extremely difficult to come here as a foreigner. You have to have a high level. All of this has helped lift the league.”