Manchester United confirmed the £19m signing of Porto full-back Diogo Dalot on Wednesday afternoon.The 19-year-old signed a five-year deal at Old Trafford after making seven senior appearances for the Portuguese club.Dalot is Mourinho's first Portuguese signing at Man United.“Joining Manchester United is an unbelievable opportunity for me," said Dalot to manutd.com."I have grown up in Porto’s Academy and I am so thankful for everything they have done for me. But the chance of coming to the biggest club in the world is something I just couldn’t turn down.“I’m excited about working with Jose Mourinho and learning everything I can from such a successful coach. I am looking forward to playing alongside the fantastic players in the squad.”Dalot is expected to provide competition to 32-year-old Antonio Valencia at right-back.

Mourinho on Dalot

The 55-year-old Man United manager made a big claim about his latest signing, suggesting there is no better young full-back in European football.

"In his age group, he is the best full-back in Europe," said Mourinho.

"He is an extremely talented young defender with all the qualities to quickly become a great player for this club."

Liverpool fans on social media couldn't let Mourinho get away with this one.

Trent Alexander-Arnold is six months younger than Dalot and has already played in a Champions League final after an excellent breakthrough season at Anfield.

Alexander-Arnold was rewarded for his brilliant season with a spot in Gareth Southgate's World Cup squad.

The 19-year-old Liverpool star is expected to make his England debut in Thursday's final World Cup warm-up match against Costa Rica at Elland Road.

Dalot faced Liverpool in the Champions League earlier this season when Porto drew 0-0 in the second leg of their knockout defeat.

Even Man United fans would struggle to argue that he's a better full-back than Alexander-Arnold at this moment.

“It was obvious he’s a big talent when we got him," said Klopp on Alexander-Arnold recently.

“Physically he was ready - he made big steps and he was still growing.

“The talent was obvious and there was only one question - was he mentally ready for the Premier League?

“He showed he absolutely is and he had an outstanding season.

“Hopefully he will have a good World Cup and I think it’s deserved and a good decision.”

Is Dalot a better full-back than Alexander-Arnold? Let us know what you think by leaving a comment below.