Borussia Dortmund's manager Jürgen Klopp has revealed Alex Ferguson admitted he failed to get the best out of Shinji Kagawa.
The Japanese playmaker signed to Manchester United in the summer of 2013 for £17m but failed to make an impression for the Red Devils.
He played just 38 times in the Premier League and scored six goals for United.
The 25-year-old netted just half-a-dozen goals for United in 38 Premier League appearances and was used mostly off the bench.
The former Manchester United manager conceded that the talented Japanese playmaker, who scored one and set up another goal on a dream second debut for Klopp's Borussia Dortmund against SC Freiburg at the weekend, was wasted at United.
Kloop (47) re-signed Kagawa for £6.3 million.
“I met Sir Alex in Nyon and he’s still in love with Shinji," Klopp was quoted as saying in The Sun on Sunday.
"He told me: ‘Shame we didn’t manage this well so that it worked out for him. We were satisfied in the first year.’
“And in the second year you usually make the next step but he didn’t manage to do it.
"But Sir Alex was saying: ‘Shame we should have made this work.’”