Much was made in the buildup to this match of José Mourinho’s managerial debt to Louis van Gaal, right up to the stiff but still horribly mawkish embrace cajoled out of the two men by the TV cameras before kick‑off. Football has a nice habit of turning such orthodoxies around though and here, in a boisterous and entertaining 1-1 draw there was an agreeable sense of role‑reversal in play.

When Mourinho came to Van Gaal he was but a pupil: when it comes to the Premier League he is, on the face of it, the master – although here Van Gaal appeared to have been studying his former assistant’s methods in England quite closely in a match in which United equalised a set-piece goal with a stoppage-time set piece of their own and, at times in the first half, pressured and disrupted a more fluid and well‑seasoned Chelsea midfield that only really asserted itself in the final half-hour.

Van Gaal had admitted after the draw at West Bromwich Albion last week that he is still adapting to the tone and texture of a new league, noticeably the need for a greater “physical balance”. And so it proved to be the case here, as Chelsea’s mobility and expertise at set pieces threatened to open up a six-point lead at the top of the Premier League right up to the final moments of a muscular, full-throated, brilliantly entertaining match.

If Chelsea left Old Trafford disappointed but still with the air of a title-bound team, the unlikely star of United’s encouragingly sound performance here was a figure from the fringes. Enter: Marouane Fellaini, brought in for his first start this season, and in the opening half the dominant feature of a concussive midfield battle, before popping up at the end to head down a free-kick, enabling Robin van Persie to drive home the equaliser.

Louis van Gaal: Manchester United not at best against Chelsea – link to video

Here Van Gaal used Fellaini like a man very deliberately placing a platoon of traffic cones in the middle of the road to slow the rush-hour traffic, drawing from the Belgian a dogged and astute performance as a kind of left-sided midfield obstacle-cum-distributional hub. The expectation before this match had been that Chelsea’s well-grooved midfield would prove too much for a work-in-progress opposition. United, though, offered the rest of the Premier League a lesson in how to close down Cesc Fàbregas’s ability to dictate play. So far Fàbregas is a convincing candidate as the player of the season in his central pivot role, albeit in a league where his qualities on the ball as metronome and razor edge make him stand out at times like a world-class sniper in a blunderbuss shootout.

Here, though, he completed just five passes in the first half as Fellaini’s inclusion gave United added muscle if not exactly mobility. There is something agreeable about the great visionary Van Gaal, the process trainer, a man who divides the pitch into tessellated triangles and who breaks possession of the ball down into at least four separate stages, deciding what he really needs in this league is a big lad to get his foot in. Fellaini, of course, offers a little more than this and from the opening moments he surged grandly from box to box like a veteran front-crawler scything his way up and own the slow lane at the municipal pool.

For a while it seemed to be working: surround Fellaini with more fleet-footed team-mates and he becomes a kind of docking station for the ball, taking possession with his back to goal on the edge of the penalty area and playing as a kind of distributional hub 20 yards in from the flank, as well as offering that chugging sense of muscle at set pieces. And yet, it could not last. If Fellaini was there to stem a Chelsea strength, that strength is too well grooved and too obviously potent to be smothered for long. Even in a relatively subdued first half Eden Hazard looked seductively fluid and dexterous on the ball: by the start of the second he had begun to make his presence felt in the space in front of the back four.

First David de Gea was forced to save one on one as the Belgian cut through. Then came Chelsea’s goal, Didier Drogba pulling away from his marker – inexplicably, this was Rafael da Silva, a player the Ivorian would have hand-selected to jump with him – to glance in a powerful header from a corner.

After which Chelsea might have taken the game away from United before that last-ditch equaliser. Deprived of their first-choice striker, Diego Costa, they still looked like nicely maturing champions-in-waiting. But Van Gaal, and his unlikely midfield cog, the Belgian who came in from the cold, will also take heart from a display of gristle and substance.