Manchester United won 2-0 on Tuesday night through goals from Robin van Persie and Ashley Young, as Juan Mata started his first United game.
Below are five things learned from United's victory:
The gravity of the Mata signing was there for all to see
The former Chelsea man provided the players and the crowd with an inevitable lift as United made an impressive start against Cardiff. Much like Mesut Ozil's arrival at Arsenal, a superstar arriving at the club helped everyone forget the doom and gloom of recent weeks and inject an immediate positivity into the club. And again like Ozil, despite being a player many think United didn't necessarily need, he is the perfect individual to remind those at the club of its status, and ensure they are stepping up to that level. Ashley Young certainly responded, with his best performance of the season as he outshone United's record signing.
The Spaniard may take a while to adjust reach his Chelsea heights
Thrust in behind Robin van Persie, Mata had a decent game without being able to really impose himself on play. It's understandable after such limited time training with his new teammates that the World Cup winner would be a little off the pace, and the playmaker was somewhat short with some of his passing and the few opportunities he had on goal. It may take a few weeks at least for Mata to settle in and start to show some proper form again, but having displayed class for Valencia, Chelsea and Spain, what is sure is that it will only be a matter of time.
The match showed that United's midfield problems haven't been solved by Juan Mata's arrival
There were spells between the two goals that United struggled to assert their authority on the match, and it was easy to see that the central midfield continued to be the problem. It's strange that with Mata joining such strong attacking talent already at the club, there is a central defender and a 40-year-old employed in the most important area of the team. Surely that is the next area Moyes will be looking to spend money on.
A fit and on form Van Persie is as good as any signing
After featuring in just 2 of United's last 17 games because of injury before the Cardiff game, it's easy to forget how much a player of Van Persie's ability would be missed. That United have lost 5 and drawn 3 of those games only emphasises the fact further, and the Dutchman returned on Tuesday night to score his 11th goal in 17 games and provide the Reds with genuine quality upfront. If Moyes can keep him fit for the rest of the season he will surely fire the club onwards and upwards. 
SEE ALSO: United and Arsenal striker target dropped from Bayern squad as rumours intensify
Fitting Rooney and Januzaj alongside Mata will be a conundrum
Moyes started the two on the bench, with his new signing up front behind the returning Van Persie, and it will be some work to fit all four into his starting lineup. Van Persie, Rooney and Mata will all expect to be central figures at the club, while it would be harsh to drop the precociously talented Januzaj, who has at times carried United recently. The only way all could play would be if Mata and Januzaj operated as the wide players in an attacking midfield three, behind Van Persie and either side of Rooney, meaning that United would go on to lose the width they have historically been associated with.  
How should David Moyes employ Juan Mata in order to get the most out of his record signing?
image: © crystiancruz