United are fifth and trail fourth-placed Manchester City by four points, albeit with a game in hand.
Mourinho’s men have drawn nine of their 16 home league games and collected more points on their travels than at home.
Mata hopes United's home fortunes change when they host leaders Chelsea on Sunday.
"We will fight until the end to be in the top four, and in order to do so we need mainly to get better at Old Trafford, at home," Mata wrote in his blog.
"We have an opportunity the next weekend against the leaders Chelsea. It's one of those games that everybody wants to play."
Mata might not play again this season after he underwent groin surgery last month but the Spain midfielder hopes to make a swift return.
"When you're injured you feel like time goes by very slow, that's the truth, and my week seemed longer than usual," he said.
"I hope that things keep going well and I can be back soon to enjoy what I like so much: training and playing football."
While a top-four finish secures participation in next season's Champions League, they could also get there by winning the Europa League.
United will travel to Belgium for their clash against Anderlecht on Thursday in the quarter-final first leg of the second-tier European club competition.