As reported by Sky Sports, Mourinho hints that Mata didn't make any improvement on some areas of the pitch, despite playing some "good matches" out of position for the side:
I am sorry that I didn't make him a stronger player. Maybe it was something new for him, not to be a first choice (player) in a difficult moment.
Maybe that made him, as a man, as a player, stronger but I gave him nothing to be honest and I feel sorry with that.
Mourinho's sporadic use of Mata left many perplexed during the last few months. As written by Jim White of The Telegraph back in September, it had seemed the player's inability to adapt confirmed he would remain at Stamford Bridge for a limited time.
"The Chelsea manager said there were 'issues' between him and Mata and hinted the player, who wants to play in the 'No 10' role, would not command a regular place in the team unless he was prepared to adapt to a wider position with more defensive duties."
Mata's lack of physical presence is often called into question when discussing his defensive output, while an absence of blistering pace ensures he isn't the type of player who quickly tracks back to help out.
As we can see from the table below, he rarely aided Chelsea's quest for clean sheets during the course of the current campaign:
|Juan Mata Defensive Comparison 2013-14|
|Name||Premier League and Champions League Starts (Substitute Appearances)||Tackles per app.||Interceptions||Fouls||Clearances|
|Juan Mata||12 (3)||1.1||0.2||0.5||0.2|
|Eden Hazard||24 (2)||0.7||0.6||0.5||0.2|
While Mata appears to lack a natural affinity for shutting the opposition down, many Chelsea fans will be disappointed to see one of the Premier League's most creative midfielders strengthen the cause of their rivals, per OptaJoe:
There's no doubting Mata lacks the physical readiness Mourinho enforces on his side, but in another setup, he could excel to the levels that saw him voted Chelsea's Player of the Year for two seasons running.
At United, Mata is likely to focus on setting up and scoring goals, not his ability to track the opposition's wingers.
Perhaps his defensive shortcomings will be balanced out by Wayne Rooney, who often drops exceedingly low to help his team overcome danger.
This has the capacity to leave David Moyes' men short in attack, but Mata could provide the counter-attacking link that will allow Rooney to satisfy his natural instincts without isolating Robin van Persie up top.
United fans certainly won't be bothered by Mourinho's comments and will be jubilant to have plucked a top player away from fierce opposition.
Moyes certainly took advantage of an excellent opportunity to land the Spaniard, as in the summer, an array of potential suitors may have looked to snap the 25-year-old up.