The Japan international signed a four-year contract with the Bundesliga outfit on Sunday after Dortmund agreed a £6.3m deal with United for the Asian playmaker.
I’m sure both Borussia Dortmund and fans everywhere will enjoy his football again
The 25-year-old called time on a disappointing two-year spell with the 20-time English champions after joining United from Dortmund in a £14m deal in summer 2012.
Kagawa scored six goals in 20 Premier League appearances under Sir Alex Ferguson but failed to impress the Scot’s predecessor David Moyes last season.
Spain international Mata was quick to talk up Kagawa’s qualities, hailing the Japanese star as a “fantastic player”.
“I would also like to wish all the best to Shinji Kagawa, a fantastic player but especially a great person,” Mata wrote on his blog, One Hour Behind.
“It’s been a pleasure to be his team-mate and I’m sure both Borussia Dortmund and fans everywhere will enjoy his football again.”
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