Wolfsburg sporting director Klaus Allofs feels his side were unable to keep hold of Kevin De Bruyne because Manchester City are a club operating without limits.
The German giants, who finished second in the Bundesliga last term, fought tooth and nail to keep hold of the Belgian midfielder, but eventually crumbled under the weight of a big-money offer from Manchester City.
De Bruyne eventually moved for a reported £55m and Allofs admits that the transfer saga kept Wolfsburg up throughout the summer months, before they then gave in and relented.
"We were busy looking at the best option day and night", Allofs was quoted as saying by Dutch outlet Voetbal Krant.
"What happened was unprecedented. Wolfsburg have their limits. Manchester City do not."
De Bruyne has made a positive impact with the Citizens so far and will be desperate to help the club recover from losing their opening Champions League game to Juventus.
relatedNewsStory
Manchester City lock horns with Borussia Monchengladbach on Wednesday, a game that will represent De Bruyne's first return to Germany since he left Wolfsburg.
De Bruyne clocked up all 90 minutes for Manchester City at the weekend when the Citizens slumped to a surprise 4-1 defeat to Tottenham Hotspur at White Hart Lane.
Wolfsburg meanwhile head to Manchester on Wednesday to lock horns with Manchester United.
