Jamie Redknapp: Juan Mata Can Give Manchester United 'Quality' Frontline

Only time will tell whether Jose Mourinho has made the right decision in selling Juan Mata to Manchester United - but one things for sure, the Portuguese boss won't regret it.

Mourinho has shown before he's not afraid of being ruthless to big name players - he sidelined Real Madrid captain Iker Casillas when he was at the Bernabeu - and I haven't got a problem with that at all.

Managers are under a lot of pressure and get the sack if things go wrong so they have to do what they feel is the right thing to do. They shouldn't be dictated to by anyone, whether that's the owners, pundits or fans.

Mata won the Chelsea Player of the Year award two years running before Mourinho returned to the club but if the manager doesn't feel the Spaniard works diligently enough when they don't have the ball, slows the game down in transition or doesn't fit into the mould Jose likes his players to fit into then he has to act.

He'd obviously looked at a lot of videos of Mata and Chelsea and thought 'no, he's not for me, I have other players that can win me games', and that's his call.

It helps when you have the sense of security that Mourinho has at Chelsea and the owner believes in what you're doing when you're making key decisions like that but I think it was a decision he probably made before he got to the club.

That's a shame because if Mourinho had gone in there and put his arm around Mata then he could have made him an even better player. Unfortunately he didn't see that as the case.

Personally, I think Mata is a fabulous little player.

His confidence has been beaten down this season so we haven't seen the best of him but he's a World Cup winner and a Champions League winner - and you can't say that just because Mourinho doesn't want him then he's not good enough for the top clubs.

Most other managers would have gone to Chelsea and built a team around Mata and I think he's Man United's gain.

Of course, if Chelsea go on and win the league this year then I'll happily say Mourinho got it spot on. But, if they don't, you can't say they are a better team without him. Time will tell.

The transfer is great news for Manchester United and their fans, though.

When United get Robin van Persie and Wayne Rooney fit and play them alongside Mata and Adnan Januzaj they will have a quality frontline which will strike fear into anybody.

But does one signing fix their problems? No, I don't think it does.

Although the £37m spent on Mata - which is a great profit for Chelsea and perhaps £10m more than I thought he'd go for - suggests the owners are prepared to pay big money, United need at least five or six new signings to get back to the top of the tree.

United need defenders and they need another midfield player. They've got a left back out of contract in Patrice Evra, they've got centre-backs in Rio Ferdinand and Nemanja Vidic who may be leaving, full-back Rafael makes a mistake in almost every game and they can't keep relying on Ryan Giggs, either.

Two years ago, before they signed Van Persie, they didn't win a trophy so this has been coming and now they need to make a number of signings to replenish the squad. You can't do that all at once, though, it will be a slow change.

Moyes' first big signing, Marouane Fellaini was a mistake and he needs to get the next ones right.

Bringing in Mata is a good start - he's a game changer who will score goals - but Moyes still has plenty of work to do before United can start to challenge at the top of the Premier League again.