'Unstoppable' Rashford the catalyst for Man Utd's Ten Hag turnaround
Rashford's winner secured a ninth consecutive win for the Red Devils since Cristiano Ronaldo's last game for the club in November.
Ronaldo's acrimonious departure threated to derail the progress being made under Ten Hag.
But shorn of the melodrama surrounding the five-time Ballon d'Or winner, United are thriving with Rashford taking centre stage.
The England international now has 16 goals for United this season and has scored in nine straight games at Old Trafford.
Rashford looked like he might be forced off with an injury during the first half against City, but battled on to net the decisive goal eight minutes from time.
"He's unstoppable," said Ten Hag. "Opponents will go tough against him to stop him. He keeps going, keeps focusing for his chances and in the end he got his reward."
Victory was all the more sweet for United as it came just over three months on from a humiliating 6-3 defeat in Ten Hag's first taste of the Manchester derby.
'Proper team'
United have lost just once in 19 games since to climb up to third in the Premier League and remain in the hunt to end six years without a trophy in the Europa League, FA Cup and League Cup.
Few could have seen that coming after Ten Hag's reign got off to a disastrous start with embarrassing defeats to Brighton and Brentford.
But the Dutchman is quickly making his mark in restoring old standards to United both on and off the field.
Even amid his scoring streak, Rashford was dropped for a 1-0 win at Wolves last month after turning up late to a team meeting.
Crucially Ten Hag's demand for discipline has buy in from his players.
"We look like a team now," Bruno Fernandes told BT. "Some months ago, you could see sometimes a team, sometimes each one of us looking for ourselves but now you see a proper team that works hard for each other."
United could easily have crumbled after City took control of the game after half-time and got their reward when Jack Grealish headed in Kevin De Bruyne's cross on the hour mark.
Ten Hag's men got the slice of fortune they needed when Fernandes' controversial equaliser was allowed to stand despite Rashford being clearly in an offside position as they both ran onto Casemiro's through ball.
With City still rocking, Rashford took full advantage with a predatory finish from Alejandro Garnacho's pass in scenes reminiscent of United's glory days under Alex Ferguson.
In the 10 years since Ferguson's farewell, United have never finished above City in the Premier League.
Just one point now separates the Manchester giants and league leaders Arsenal are now in United's sights ahead of their trip to the Emirates next weekend.
"One of the main jobs for a manager, coaching staff, is to work on the mentality of the team," added Ten Hag. "That has a lot of elements and one of them is resilience.
"This team is progressing a lot in dealing with setbacks, suffering, dealing with painful moments, like a goal against. We have players on the pitch who have the experience that in one moment things can change."
Ten Hag has already made sweeping changes in his first six months in charge.
But his most telling impact has been on in restoring the confidence of a player that has been at the club his whole career.
Rashford scored just five goals last season as his fitness and form deserted him after the arrivals of Ronaldo and Jadon Sancho pushed him down the pecking order.
Now he's rising to the occasion as United's main man.
