It was the day that Manchester well and truly put London in its place. The new capital of football could hardly have made a more forceful argument, winning 13-3 on aggregate – and it was a scoreline that didn’t flatter the city.

United dished out a beating to Arsenal just hours later – putting eight past their old rivals.

Wayne Rooney’s hat-trick and two pearls from Ashley Young were the highlights of an unforgettable 8-2 win that backed up every argument that the Premier League title would be a two-horse race.

But what has happened since?

While United remain on top – Arsenal have kept pace admirably.

They have been allowed to fly under the radar while the Manchester United have grabbed the headlines.

Here M.E.N Sport’s James Robson looks at the form of both sides since that remarkable Sunday in August – and just who will triumph in what promises to be one of the most exciting title races of all time.

United

That United are only three points adrift of City at the top of the table is nothing short of a minor miracle. Sir Alex Ferguson’s side has been decimated by injuries to key players – most notably Nemanja Vidic and Tom Cleverley.

As feared, he has struggled to replace Edwin van der Sar with David de Gea now being removed from the spotlight after a series of high-profile blunders.

He failed to sign a world-class successor for Paul Scholes – and following injury to Cleverley has only been saved by the ginger magician’s shock decision to come out of retirement.

The truth is it could have been even better for United if not for back-to-back defeats to Blackburn and Newcastle over New Year.

That the champions remain in touching distance is an ominous sign for their rivals. Ferguson’s teams traditionally come on strong in the second half of the season and with the injury list beginning to clear up, he could soon have a near full-strength squad to call upon.

Cleverley will be like a new signing – and there is still time for Fergie to enter the transfer market before the end of January.

United’s title-winning know-how could prove their greatest asset in the closing stages with both City and Tottenham in unchartered waters.

Arsenal

The 8-2 at Old Trafford was Arsene Wenger’s most humiliating day in management. Unfortunately for the Frenchman, he has been humbled many more times since.

That mauling was enough to prompt him to make a supermarket dash on transfer deadline day, bringing in Mikel Arteta, Per Mertesacker and Andre Santos. But Arsenal have rarely looked so far from genuine title-challengers under Wenger.

In truth, a top-four finish is their main target this season – one that is by no means guaranteed with Chelsea and Liverpool also in competition.

The 4-3 defeat at Blackburn in September was another low, as were back-to-back defeats to Fulham and Swansea in their last two league games.

Thierry Henry might have returned to an emotional fanfare but even he is falling out with supporters now.

Most worrying for Gunners fans is that for the first time in Wenger’s reign there is no clear sign of progress.

His current Arsenal side is not a team in transition, as has been argued for much of the last eight years since their last title success.

Robin van Persie is the new figurehead of the club – but how long until he goes the way of Henry and Cesc Fabregas before him and heads through the exit door and to the promise of trophies elsewhere?

Jack Wilshere is the man Arsenal’s future hopes rely on – but at the moment he simply doesn’t have enough quality around him at the club.