The London Evening Standard says a Dortmund insider has revealed that Kagawa has already shaken off his United disappointment and is looking as good as ever.
It took him just two minutes to score his first goal in training and he is set to play a major role under manager Jurgen Klopp.
People within BVB were shocked that United did not get more out of the Japan international and were surprised that they were allowed to buy him back so soon and so cheaply.
The coaching staff have been amazed at how quickly he has got up to speed with their methods and are expecting him to make a big impact.
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