Manchester City's two-season ban from UEFA competitions has been quashed by the Court of Arbitration for Sport (CAS).
In February, the Premier League club were accused of committing "serious breaches" of UEFA's club licencing and financial fair play (FFP) regulations, and handed a two-season suspension.
UEFA's independent Adjudicatory Chamber of its Club Financial Control Body (CFCB) also fined City €30million after concluding they had overstated sponsorship revenues in accounts submitted to European football's governing body between 2012 and 2016.
City have persistently denied wrongdoing in relation to the matter, and CAS found in their favour in a verdict announced on Monday.
"Manchester City FC did not disguise equity funding as sponsorship contributions but did fail to cooperate with the UEFA authorities," read the heading to the CAS statement.
City must pay a reduced fine of €10m for that failure to assist UEFA adequately in its investigations.
CAS found a significant number of the allegations made against City to be "time-barred" and therefore concluded there were insufficient grounds to uphold the ban.
UEFA previously punished City with a €60m fine and spending cap, along with a restriction in their Champions League squad size for the 2014-15 season, after finding them guilty of FFP breaches in May 2014.
"The CAS award emphasized that most of the alleged breaches reported by the Adjudicatory Chamber of the CFCB were either not established or time-barred," said CAS, which will publish its full written reasons over the coming days.
"As the charges with respect to any dishonest concealment of equity funding were clearly more significant violations than obstructing the CFCB's investigations, it was not appropriate to impose a ban on participating in
UEFA's club competitions for MCFC's failure to cooperate with the CFCB's investigations alone."
When their punishment was handed down, City criticised a "prejudicial process" from UEFA and the club was quick to welcome the CAS ruling.
"Whilst Manchester City and its legal advisors are yet to review the full ruling by the Court of Arbitration for Sport, the club welcomes the implications of today’s ruling as a validation of the club’s position and the body of evidence that it was able to present," a statement read.
"The club wishes to thank the panel members for their diligence and the due process that they administered."
Questions will now be asked over the long-term viability of UEFA's FFP model after the outcome of what could come to be viewed as a landmark ruling.
However, the governing body said it remained "committed to its principles" in a statement reacting to the verdict.
"UEFA notes that the CAS panel found that there was insufficient conclusive evidence to uphold all of the CFCB’s conclusions in this specific case and that many of the alleged breaches were time-barred due to the five-year time period foreseen in the UEFA regulations," a statement read.
"Over the last few years, Financial Fair Play has played a significant role in protecting clubs and helping them become financially sustainable and UEFA and ECA remain committed to its principles."
City hold a 2-1 advantage over Real Madrid after the first leg of their last-16 tie in this season's Champions League. The second leg will take place at the Etihad Stadium on August 7.
Pep Guardiola is yet to take the club beyond the quarter-finals in a tenure that started in 2016.