The Japanese scored and provided and assist on his return for Borussia Dortmund so how come Manchester United failed so miserably in getting the best from a clearly talented player?

There was one picture that stood out last week as Shinji Kagawa was back in training with Borussia Dortmund. Jürgen Klopp, clearly delighted to have his Japanese superstar back, had his arm tenderly around the 25-year-old’s shoulder. Both were smiling.

Looking at the picture it was impossible not to wonder whether Sir Alex Ferguson, David Moyes or Louis van Gaal had ever tried something similar during the Japanese’s miserable two-year spell in England – and whether such a warm approach is crucial in order to get the playmaker to produce the kind of football he is so obviously capable of.

The Dortmund fans are delighted to have him back and flocked to an autograph signing session last Wednesday while the sales of his No7 shirt have vastly outnumbered those of Bayern’s signings from late August, Mehdi Benatia and Xabi Alonso. As far as reunions go, this one has the potential to be remarkably successful.

One thing Kagawa will not be afforded, however, is a gradual reintegration into the team with which he won the Bundesliga title in 2011 and 2012. With Marco Reus out injured for four weeks the Japanese will be expected to play a significant part when Arsenal visit in the Champions League on Tuesday. Kagawa may even start in the No10 role as Dortmund struggle with injury problems before a tie they lost 1-0 last season, thanks to an Aaron Ramsey goal.

Apart from Reus, Klopp is likely to be without the following midfielders against Arsenal: Oliver Kirch, Nuri Sahin, Jakub Blaszczykowski and Ilkay Gündogan, although the latter is actually nearing a first-team return after terrible injury problems over the past two seasons. Jonas Hofmann, another option in attacking midfield, has been loaned to Mainz.

Klopp said: “I had 15 players available [against Freiburg on Saturday] so I can’t just say to Shinji: ‘Hey, why don’t you sit in the stands and take in a bit of the atmosphere.’ He will be needed. I can’t wait a few weeks.”

As it was, Kagawa celebrated his second debut for Dortmund with a goal and an assist in the 3-1 win against Freiburg, before leaving the pitch after suffering from cramps. “Today I had goosebumps the whole time. It was very refreshing and a joy to play again in this stadium,” he said afterwards.

Will there be a reaction against Arsenal? Quite possibly, and Hans-Joachim Watzke, the Dortmund chief executive who concluded the cut-price, £6.3m return of “the lost son” – as Kagawa has been labelled – is fully aware that they will need to be patient before Kagawa is back to his best.

“We have to give him time,” Watzke told Die Welt. “He was our No10 in some very successful years and then it is understandable that the fans’ fantasies take flight [when he returns]. But we will not overload him with expectations.

“The fact is that he has not ‘unlearnt’ how to play football. He has just lost a bit of confidence, although he hasn’t played as little at Manchester United as some people seem to think. Clearly the time at United did not unfold as he had hoped it would so now we have to massage his soul and that is what we are doing.

“We are sure that he will get the peace, the time and the appreciation he needs to get back to his absolute best. The people here have longed for him for two years and what is happening here at the moment is nothing short of massive hype.”

“Massive hype”? No pressure then Shinji…? Either way, it will be fascinating to see whether Klopp can restore Kagawa’s powers. There is a precedent, of course, with Sahin, who left Dortmund for Real Madrid and ended up at Liverpool at the start of the 2012-13 season. Come January, Sahin was back at the Westfalenstadion, saying: “I did not fail at Liverpool. Brendan Rodgers wanted me to play as a No10. But I do not play behind the strikers. I talked to him and asked him why he was playing me there. It is not my real position. The coach could not answer me …thank God I have left Brendan Rodgers.”

Kagawa would probably say similar things about his managers at Manchester United, but then he is too polite for that. The stats can do all the talking instead. For Dortmund he scored 21 goals in 49 league games, while at United that figure was six in 38 games. He created 77 chances for Dortmund in those games while the corresponding figure for United was 35. No wonder he is happy to be back.

“I did actually say in my farewell interview that for me the Borussia Dortmund chapter wasn’t closed,” Kagawa said at his unveiling. “I wanted to fulfil a dream in the Premier League but now I am simply pleased to be back at Dortmund again, with this great team, these incredible surroundings and the unique fans. BVB is like a family and I am proud that they have not forgotten me and that I once again belong to this family.”

One thing is for sure. Kagawa will once again be able to feel that he is appreciated and trusted by his manager. There are also likely to be a few more laughs than there were at Old Trafford or Carrington. At last Thursday’s press conference Klopp was asked in what language he was communicating with Kagawa. “Japanese,” quipped the Dortmund manager, then he smiled, and stood up.