Alvaro Carreras has been a revelation at Real Madrid. After pocketing Lamine Yamal in El Clasico, the left-back blasted home his first Madrid goal against Valencia on Saturday evening. Why on earth did Manchester United allow him to leave Old Trafford?

As he makes his return to the North West of England for Real Madrid's Champions League game against Liverpool on Tuesday night, it is Carreras rather than Trent Alexander-Arnold who looks the pick of the club's new signings under Xabi Alonso.

Having blossomed at Benfica, the 22-year-old already appears a bargain buy - even at the £43m fee that Madrid paid for him. It all seems a little strange when United were muddling through with Sergio Reguilon and Sofyan Amrabat at left-back not long ago.

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Alvaro Carreras scored his first Real Madrid goal with a screamer against Valencia

Instead, Carreras' only first-team football in England came on loan at Preston North End, where there is similar disbelief. "I just cannot believe that United did...