The Red Devils slumped to a surprise loss to the Premier League strugglers at St James’ Park to leave Manchester United 16 points behind leaders Manchester City.
The 20-time English champions conceded a second-half winner after Scotland international Matt Ritchie left Jose Mourinho winless in seven trips to St James’ Park.
Manchester United are two points ahead of third-placed Liverpool FC as the race to secure a top-four finish hots up in the final months of the 2017-18 season.
The Red Devils will host Premier League rivals Huddersfield Town in the FA Cup fifth round next weekend before Manchester United make the trip to Sevilla in the Champions League round of 16 next week.
Mata explained to Manchester United fans how the Red Devils will bounce back from their disappointment at Newcastle.
“Unfortunately this is one of those days when you don’t feel in the best mood to update your blog, neither do you to read it,” Mata wrote in his personal blog.
“It’s not easy to write after a defeat. The truth is, after losing an away game you think a lot about it on your way back home.
“You remember every play, every moment, and you try to change the outcome but obviously that’s impossible. You can’t turn back time, so the only way to carry on is to turn all this rage into a desire to win, work and attitude for the next game.
“The 1-0 in Newcastle hurts because we had chances to score both in the first and in the second half, but they took better advantage of their weapons.”
Manchester United finished in sixth place in the Premier League table last season to miss out on a Champions League spot.
The Red Devils were 2-0 winners against Ajax in the Europa League final to secure a return to Europe’s premier club competition.
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