The Red Devils are in second place in the Premier League table and four points ahead of Liverpool FC and Tottenham Hotspur.
Manchester United looked to be heading for an embarrassing loss to the Citizens after first-half goals from Vincent Kompany and Ilkay Gundogan.
However, Jose Mourinho’s men rallied in the second half and Paul Pogba scored twice to level the Manchester derby.
The Red Devils secured an unlikely three points after Chris Smalling scored from a set piece to get revenge for a 2-1 loss to their rivals at Old Trafford back in December.
Manchester United can edge one step closer to securing runners up spot if the Red Devils can beat 20th placed West Brom in their next Premier League on Sunday.
Mata warned Manchester United that the Baggies will be fighting for their lives at Old Trafford this weekend.
“The most immediate game in the calendar is against West Brom, next Sunday at Old Trafford,” Mata wrote on his personal blog One Hour Behind.
“I’m sure the atmosphere will be very positive, so we must take the opportunity to put on a good game and a win for our fans. West Brom are the bottom team and that indicates how important and decisive the game will be for them; they need points.
“Us, we must show why we are second on the table.”
Manchester United signed Alexis Sanchez in a swap deal from Arsenal in the January transfer window.
The Red Devils finished in sixth place in the Premier League table last term but won the EFL Cup and Europa League.
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