It was the moment manager Louis van Gaal had been dreaming of: Manchester United stopping a run of four straight derby league defeats against Manchester City and shifting the power in the city from blue to red.
Not since November 2013, when United were sixth and City were ninth, has the red half of Manchester been above the blue half in the Premier League, but City's sudden loss of form has allowed their neighbours to climb above them for the first time in 18 months.
United, who finished seventh and 22 points behind champions City last season, have finally found their feet under Dutchman Van Gaal and they crushed their local rivals 4-2 at Old Trafford on Sunday to claim a sixth successive Premier League victory.
Van Gaal's formula for success has seen Wayne Rooney deployed further forward, Juan Mata on the right, and Marouane Fellaini as a deep-lying target man, anchored by a midfield combination of Michael Carrick and Ander Herrera.
After a slow start against City, United burst into life and the impressive Ashley Young grabbed an equaliser before setting up midfielder Fellaini who has been rejuvenated under Van Gaal this season.
Spaniard Mata, another player enjoying his best spell at United since joining from Chelsea last season, scored a third and England defender Chris Smalling capped off a fine display to hand United victory in the 169th Manchester derby.
"It's process and I have said that when the players do understand what they are doing on the pitch then we can continue much more easily than before," Van Gaal told reporters when asked about United's end of season resurgence.
"A lot of players do understand what we are doing and are willing to perform."
Third-placed United, who play leaders Chelsea at Stamford Bridge next weekend, have 65 points from 32 matches, four more than City with six matches remaining.
Having masterminded City's downfall, Van Gaal said it was a good time to be a United fan but the Dutchman admitted there is a long way to go before the end of the season.
"We can enjoy ourselves today and tomorrow maybe. But then we have to prepare to play Chelsea," he said.
"In the beginning of the season it was not so great to be a United fan. Still they have supported us and now this week they can go on the streets and say we are the better team this year."
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