Ole Gunnar Solskjaer’s side bounced back from their embarrassing defeat to Tottenham before the international break with a 4-1 win at St James’ Park on Saturday.
The Red Devils fell behind after just two minutes through Luke Shaw’s own goal but captain Harry Maguire headed home an equaliser midway through the first half.
Manchester United dominated the second period and scored three goals in the final 10 minutes, with Fernandes, Rashford and Aaron Wan-Bissaka all netting.
Premier League legend Shearer was impressed by United’s performance and reserved special praise for Fernandes, Rashford and Mata.
He said on Match of the Day: ‘Ole Gunnar Solskjaer deserves credit for changing the team. That team needed to be changed after their last performance and they played very well.
‘They battered Newcastle. I thought Fernandes and Mata were so clever. They stood in those little pockets, in those holes, and Newcastle couldn’t handle it.
‘They were just too good on the ball and showed so much creativity. Those two on the ball, they can punish teams and they caused problems all evening.
‘Rashford was excellent as well with his goal and two assists. The weight of passing from United was brilliant.
Fernandes, who missed a penalty before scoring for Manchester United, said: ‘The motivation was for winning.
‘Of course, I was frustrated to miss a penalty but we had a great reaction afterwards.
‘The last goal for Rash was deserved because he did a really good game today, but this win is for the whole team.
‘It’s always important to win. To have criticism is normal in football. This is a big club, we have big pressure, but we are big players.
‘We are OK for that. The team is together. Today is a right way to reply to the 6-1 against Tottenham.’