Manchester United back in top four race after derby win

Manchester City ^[1] 0 Manchester United ^[2] 1

There has not been a surplus of material for Manchester United's highlights reel this season but amid all the disappointments, the lost points and fervent debate about Louis van Gaal's suitability for the job, they chose a good moment to remember some of their old qualities from days gone by when these kind of joys were the norm rather than the exception.

Perhaps the greatest compliment that can be paid to Van Gaal's men – and, admittedly, it is a back-handed one – is that they played as though affronted by the suspicion that has been circling that Van Gaal has put together the most undistinguished team to emanate from Old Trafford for almost 30 years. They have unearthed another gem in Marcus Rashford, scorer of the game's decisive moment, and on this evidence it is perfectly plausible for them to think they can overhaul Manchester City to claim the fourth Champions League place.

For City, that represents a considerable embarrassment given the various ordeals that Van Gaal has encountered this season and the deception going back to last autumn of Manuel Pellegrini's team winning their first five matches. Their deterioration since then is bordering on a full-on slump, one that could conceivably leave them in the Europa League next season, and for a club whose supporters like to sing how they "fight to the end" the truth is they folded far too easily.

Martín Demichelis suffered such a torrid time he was substituted early in the second half, largely to prevent him being a danger to his own team.

Demichelis was badly at fault for the goal, fortunate not to give away a penalty and partly responsible for Joe Hart ^[3] injuring himself when he underhit a back-pass to City's goalkeeper and almost let in Anthony Martial ^[4]. It was a tragicomedy of such proportions it would not be a surprise if Demichelis, appr oaching the end of his contract, is not seen in City's colours again but, in fairness, he was not the only player to suffer. City look like a team that need to be reinvented and their crowd must be longing for Pep Guardiola's restorative powers.

United, in stark contrast, must be encouraged by one of their least exacting visits to this stadium and Rashford's contribution certainly justified Van Gaal's decision to keep him in the team after a couple of peripheral performances. Rashford, the only Mancunian on the pitch, has provided some of United's more illuminating moments this season and his latest one was his outstanding piece of centre-forward play yet.

The 18-year-old was 30 yards from goal when Juan Mata ^[5] played the ball but it was a lovely piece of soft-touch control to lure Demichelis into the first of several rusty challenges. Rashford was waiting for his opponent's body movement and his second touch took him away in a flash. It had happened in a blur and he took the chance as though immune to nerves, adjusting his body shape to improve his angle and then placing his shot past the oncoming Joe Hart.

The goal was a personal ordeal for Demichelis and these are the moments when a player of 35 must wonder whether these younger, quicker opponents are ushering him into retirement. The harsh reality is that he cannot cope at this level any more and, just before half-time, there was more evidence of his decline when Morgan Schneiderlin's improvisational flick sent Rashford darting in from the left. Demichelis was too slow again, arrived late and turned his side into Rashford. It was a clear penalty despite some amateur dramatics from several City players, in particular Fernando and Demichelis, to argue it was a dive and United were entitled to be aggrieved that the referee, Michael Oliver, waved play on.

Fernando had been brought on after 26 minutes because Raheem Sterling had been hurt in a challenge with Juan Mata. Yaya Touré was moved further forward, with David Silva ^[6] taking Sterling's position on the left, but with the exception of Sergio Agüero it was a sleepwalking performance from City throughout the remainder of the first half. They had started the game encouragingly, with Agüero frequently getting the better of Chris Smalling ^[7], but it must have been alarming for Pellegrini to see his team's fitful response to going behind.

Unfortunately for Pellegrini, this is becoming a recurring theme of a season when City have now gone 22 games without recording back-to-back wins and, even more startlingly, managed only two victories in 14 matches against top-half teams all season. City's total of 51 points from 30 games is an accurate barometer compared to the corresponding stage of the previous four seasons – 61, 67, 62 and 70 – and even when they pinned back their opponents for a 20-minute spell in the second half, Agüero heading one chance against the post, it was not with the guile of old.

For United, everything looked so much more rounded without Marouane Fellaini cluttering up the place. Jesse Lingard ^[8] might not be a natural No 10 but the tactic worked much better here than it had done against Liverpool last Thursday. Mata was prominently involved and Anthony Martial always looked dangerous when he took on the left and then set off infield.

As for Rashford, it was harsh in the extreme that the official man-of-the-match award went to Chris Smalling.

Smalling had actually found Agüero a difficult opponent and, having already been booked for a first-half trip, he was fortunate not to be sent off after another challenge on the same player. This time United benefited from some debatable refereeing and Van Gaal's team could celebrate their finest moment of a difficult season.

(Guardian service)