Manchester United defeated local rivals Manchester City 4-2 at Old Trafford to solidify third position in the Premier League table. A Sergio Aguero brace sandwiched goals from man of the match Ashley Young, Marouane Fellaini, Juan Mata and Chris Smalling, who erased bad memories of the reverse fixture in which he was sent off.

It was United’s sixth consecutive win in the league as they continued their fine form in a tough run of fixtures in recent weeks. They have now beaten Liverpool, Tottenham and City in three of their last four games.

Here are five key thoughts following United’s phenomenal derby victory.

1) Manchester is Red once again

For the first time since December 2012, United won the Manchester derby against their local rivals in emphatic style. After a shaky opening to the game, the Red Devils piled on the misery on City to gain revenge for two years of hurt. It was all the more sweet considering the two sides are in direct competition for Champions League places and it piles the pressure on Manuel Pellegrini who will be lucky to hold onto his job.

It has been too long since Robin van Persie’s last minute winner at the Etihad. United have suffered in between then and now, having been thrashed twice under David Moyes last season. On Sunday it was completely different as Louis van Gaal’s United dominated proceedings and if it wasn’t for a nervous start, would have won by more. Either way, it is great to have the bragging rights back and Manchester is well and truly red once again.

2) Pace, ferocity and purpose – United too much for City to handle

Van Gaal has tinkered with his tactics all season but finally, he has found the system that suits the players at his disposal and it has led to a free-flowing, energetic style of play which United fans have been craving since Sir Alex Ferguson left the club two years ago. They outplayed City with sheer pace and ferocity both in and out of possession and it was too much for last season’s champions to handle.

United pressed high, forcing City into mistakes and when they did have possession, they were able to retain it and use it effectively. They ripped the City defence to shreds at times with neat, intricate passing moves and even delivered some quality balls into the box consistently and effectively. There is a purpose and team spirit about United at the moment and it is fantastic to watch. The future is bright.

3) The Young, Fellaini and Blind triangle reaps havoc down the left

Ashley Young is a player re-born. His two assists and equaliser were enough to get him the man of the match award but he was lively and direct throughout the game. The same goes for Marouane Fellaini. He has been a revelation in a United shirt this season and has completely transformed everybody’s opinion on him. He is not just a threat in the air anymore, he is starting to bring down long balls and instigate attacks down the left in tandem with Young and Daley Blind.

The trio reaped havoc down City’s left-hand side as they have done in previous games. The overload of the left-hand side has become a feature of their recent displays with Blind on the overlap and Young cutting inside. The first three goals all came from good work down that side of the pitch and the trio are in such good form, they have made themselves undroppable. Angel Di Maria will have to wait.

4) Smalling and Jones saved by Carrick’s experience and discipline

It was a poor day at the office for Chris Smalling and Phil Jones in central defence as they looked like making a mistake whenever the ball came near them. It was a particularly nervous start from the duo which would hardly send confidence through the rest of the team. Luckily, the quick equaliser gave United a boost and they were able to get over their defensive problems to win at a canter.

United had the presence and experience of Michael Carrick to thank for getting them over the finish line. When Jones and Smalling were constantly being dragged out of position, he was always there to mop up any danger and re-organise the backline. Neither Smalling nor Jones were convincing or looked like leading the defence so Carrick took over. It was an amazing performance from the 33-year-old, who is a vital member of this side.

5) United move four points clear of City rivals to all-but guarantee Champions League football

The win saw United give themselves a cushion over their local rivals. The four-point gap it opened up over fourth place all-but guarantees Champions League football for next season. United are now nine points clear of fifth-placed Southampton and must now look at overhauling Arsenal in second position. The Red Devils have won six in a row and are playing with supreme confidence.

Not only does the power in the North West appear to have shifted back into United’s favour but it has seen City dragged back into an unwanted battle with Southampton and Liverpool for the final top four spot. If the Reds win on Monday night, they are just four points behind City with United looking down on both of their main rivals. The first win over City in two-and-a-half years is a hugely significant one and it is just the beginning.