Fernandes' goal was the turning point and City boss Pep Guardiola and his players were seething after the flag went up for offside when Rashford ran on to Casemiro's pass.
Rashford did not touch the ball and was deemed by VAR not to have interfered with play, but City was adamant the England forward clearly distracted the defenders and goalkeeper Ederson.
"The first goal is a joke that it can be allowed," City defender Manuel Akanji told BBC Sport. "He runs for 30 meters, he's chasing the ball. In the situation, I played him [Rashford] offside. I understand he doesn't touch the ball, but for me it is clearly offside."
Guardiola insisted there was no doubt Rashford's run impacted the reactions of Akanji and Ederson.
"The decision is the referee's, the VAR, but our defenders make a line for Rashford," he said. "If we know it's Fernandes, we don't make the line, we follow the action, and after the action the interference for Ederson."
Third-place United is now just one point behind second-placed City, which is in danger of losing substantial ground in the title race this week. A win for leader Arsenal at north London rival Tottenham on Sunday would put the Gunners eight points clear.
While Citys splutter, United is in fine form following their ninth successive victory in all competitions.
Asked if it was in the title race, boss Erik ten Hag said: "The fans may dream but we are not. We have improved, that is obvious. There is still a long way to go."
Dismal Liverpool. Liverpool's hopes of salvaging a top four finish from a difficult campaign suffered a major hit as Brighton swept to victory on the south-coast.
After dominating the first half without making the breakthrough, Brighton deservedly took the lead in the 47th minute. Joel Matip carelessly surrendered possession to Alexis Mac Allister and he found Kaoru Mitoma, whose cross was perfectly weighted for the unmarked Solly March to tap in.
Liverpool was in disarray and six minutes later, March crashed a fine finish into the far corner from just inside the area.
Danny Welbeck wrapped up the victory, flicking March's pass over Joe Gomez and volleying home.
Beaten at Brentford in the previous league game, Liverpool is languishing in ninth place, seven points adrift of the top four, and look a shadow of the team that nearly won the quadruple last term.
"Bad. Really bad. I can't remember a worse game. It was a very organized team against a not very organized team," Klopp said.
Liverpool's Merseyside rival Everton is in even more dire straits after Southampton's 2-1 win at Goodison Park.
Everton's board of directors did not attend the game because of a "real and credible threat to their safety".
Everton has won only one of its last 13 matches in all competitions and banners calling for owner Farhad Moshiri to sell up were unfurled before kickoff.
Amadou Onana gave Lampard's men the lead, but James Ward-Prowse struck twice for Southampton and thousands of Everton fans staged a sit-in protest after the final whistle.
Southampton remains bottom of the table but it is now behind Everton only on goal difference.
"It's clear in football that sometimes if you aren't winning games it can become contagious in terms of confidence and we know we are in that spot," Lampard said.
West Ham fills the final place in the bottom three after a 1-0 defeat at Wolves that saw the hosts move above the hapless Hammers. Nottingham Forest beat Leicester 2-0, while Brentford defeated fourth-from-bottom Bournemouth 2-0.
smg/dj
© Agence France-Presse
English officiating appears to be circling the toilet. If a player wants to screen an opponent from the ball, (s)he needs to be 2 yards or closer to the ball for it to be legal. Rashford was closer than 2 yards to it during his pursuit of the ball, meaning he was able to screen the opponent and was involved in play. Center should have gone upstairs to get help from VAR to come to this conclusion. Definitely Offside and no one would have argued before they all got to the 18 yard box. Once the ball is in the back of the net, everyone loses their rag.
This was a great game to watch, enjoyable. These were my two favorite English teams, due to the coaches who both follow the Cruyffian philosophy. Since I don't have a DVR to go back to and check ,I was forced to watch the game at 4 different levels ,mentally. So whenever MC had ball possession, my mind was on where should the ball go, and why ,ahead of time, then question the actual movement of the ball by MC ,in case it's differernt; and at the same time I was watching how MU was setting up their defense according to MC's movement of the ball, and then see if MU defensive manuevering was trying to force MC to a certain situation or area of the field. Next, while this is going on ,I was looking to see if MC ,in ball possession when on attack, prepare defensively for any counter attacks; and turning it around where MU postioning for the counter attack, and if around the midline, who would be open for the secondary,and tertiary pass or if on the frontline who would receive the long ball........ My head was steaming after the game.
I was hoping for a tie for I didn't want either to lose. Sort of happy MU won since they got their butt kicked previously by MC. The win did leave a bitter taste in my mouth concerning the first goal by MU.. This whole off-side aspect has become a "DRAMA" due to playing and fidgeting around over the years with the 'off-side' rule , which at one time was very simple. The VAR coming into play in past few years it has made it even worse...But this whole 'offside'drama' has all come about due to tampering with the rules without knowing the consequences...
R2, brought up something interesting which I didn't know. But to me, the rule changes has come to the point where 'LOOPHOLES' are being found in the laws... As far as I'm concerned, Rashford didn't touch the ball, so he wasn't offside, but he did influence, and more so since he was in the centerlane , close in front of the the goal. If he were positioned next to sideline, on the flanks, we wouldn't have this argument.
The same can be said on free kicks whereby the one of the attackers stands behind the defensive line in an offside position. Lets not kid ourselves, short of receiving the ball directly, the only reason he's there is to try and influence the defenders, placing attention on him...
The idea that Rashford was not involved in that play is absurd.
I agree, but I have not read anywhere that mentions this aspect of playing the ball that I describe above. Most seem to believe the trailing defender has to catch up to Rashford in order to challenge for the ball. Wonder what Ian and Randy have to say. Interestingly, the AR has a better view of this and raised his flag but the center overrode it.
R2, I thought Rashford interfered with an opponent, who was two yards away, so therefore offside. Yet I could see how the goal was given. The problem is in an overly complex rule, as complicated as the American tax code, whose interpretation has recently changed. Ugh!
Make off side plain and simple with daylight....no toes, no knees, etc.
Bg, how 'bout , VAR is not employed for offside calls....That would settle 80% of this garbage...
https://www.youtube.com/watch?v=pBWL8Uj1kIw
Downside when you have the AR wait to indicate the attacker is in an offside position.
When and under which conditions to use VAR in England has still not been ironed out.