Momentum can be, well, momentous in football.

When the Invincibles lost to United (or should I say: “were Mike Rileyed* at United”?) it triggered a run of form which went LDDWDLLWD.

The greatest team in the country at the time, and arguably ever, won two games out of a possible nine, taking 10 points from a possible 24, and got themselves eliminated from the League Cup by the very same side that stopped their unbeaten run at 49 games.

In short, when the momentum stopped, we didn’t just stop with it, we completely fell over.

*For the younger fans, being Mike Rileyed was the noughties equivalent of being Mike Deaned in the modern day!

And for me, that’s sort of how it felt on Tuesday night, when over-exuberance and ill-discipline let to a clinical Barcelona counter attack.

LONDON, ENGLAND - FEBRUARY 23: Lionel Messi of Barcelona celebrates scoring the opening goal during the UEFA Champions League round of 16 first leg match between Arsenal and Barcelona on February 23, 2016 in London, United Kingdom. (Photo by Paul Gilham/Getty Images)
Urgh (Photo by Paul Gilham/Getty Images)

You could see instantly that the players felt their only chance had been to keep a clean sheet at the Emirates and try to nick a goal – as Stephen wrote so excellently on Thursday night, they were beaten by their own fear – and having conceded, they then fell to pieces after the 71st minute and frankly could have conceded any number of goals in that final quarter of the game.

Many have seemed depressed at the inevitability of Tuesday’s result, others angry.

For me, the overwhelming feeling is one of frustration.

We had the perfect game plan, we executed it perfectly, and we were more than matching the greatest team on the planet right now…until we stopped.

For those of you who have already listened to Friday’s super-duper bumper bonus podcast, you’ll have heard me talk about how irritating I’m finding it that all the talk is now of how Barcelona’s quality came through in the end, and how we just weren’t good enough again.

That’s because it’s not true.

Barcelona's Brazilian forward Neymar (2R) walks with his shirt over his head following the UEFA Champions League round of 16 1st leg football match between Arsenal and Barcelona at the Emirates Stadium in London on February 23, 2016. Barcelona won the match 2-0. / AFP / JAVIER SORIANO

We played well, although we missed a certain finishing quality, and we only lost because we shot ourselves in the foot (admittedly twice).

But crucially, that means the perception in the media, amongst fans (both ours and opposing) and of course filtering down into the club, is that we were outmanoeuvred, outplayed and outclassed.

And that’s a very dangerous mindset to be in.

Arsène himself didn’t help matters either, when – clearly fuming – he gave his post-match interview betraying that he felt let down by the performance of his players. It just added to the overwhelming cloud of misery and depression that, once again, we had lost to Barcelona, once again, we had come up short and, once again, our players had come away with absolutely nothing despite giving absolutely everything.

Winning is all that matters

It’s stark contrast to the situation this weekend’s opponents Manchester United find themselves.

If you had told them a week ago, having just lost to FC Midtjylland – a club who, by the way, are only third in the 24th best league in Europe – that they would be going into the game against us without Anthony Martial and off the back of another Thursday night Europa League clash with the Danish ‘giants’, I think they may well have turned up at Louis van Gaal’s house with burning pitchforks and a body bag.

As it is, they go into the showdown off the back of a 5-1 massacre with a youth product striker buoyed by scoring in a dream debut performance.

Manchester United's English striker Marcus Rashford (L) celebrates scoring his team's third goal with Manchester United's Spanish midfielder Juan Mata during the UEFA Europa League round of 32, second leg football match between Manchester United and and FC Midtjylland at Old Trafford in Manchester, north west England, on February 25, 2016. / AFP / OLI SCARFF
New Manchester kid on the block (OLI SCARFF/AFP/Getty Images)

No one is talking about how United made terribly hard work of beating a team who were only founded just before the millennium. No one is talking about how they were choking so badly that with less than half an hour left of the two legged tie they were 3-1 down on aggregate and facing a very embarrassing exit.

And no one is talking about how Midtjylland are ranked 124th in Europe*…any more.

*to give you an idea of quite how bad that is, there are 16 English teams above them, including three clubs who don’t even play in the Premier League any more (Birmingham City in 94th, Fulham in 95th and Wigan in 103rd).

Because in football, you’re only as good as your last performance and their last performance was, however poor, fruitful.

Whereas ours was, however good, was not.

At the next junction, please make a U-turn

Arsène may need to make a U-turn as sharp as Nick Clegg’s when he found himself in bed with the Conservative government back in 2010, if he’s to get his squad into the right headspace to win on Sunday.

There are positives from Tuesday’s game, and we very much need to take them if we are to have any chance of taking three points away from one of our biggest bogey grounds.

Barcelona's German goalkeeper Marc-Andre Ter Stegen (L) dives to save a shot from Arsenal's French striker Olivier Giroud (C) during the UEFA Champions League round of 16 1st leg football match between Arsenal and Barcelona at the Emirates Stadium in London on February 23, 2016. Barcelona won the match 2-0. / AFP / ADRIAN DENNIS
Wonder save denies Arsenal. Again. (ADRIAN DENNIS/AFP/Getty Images)

We created chances, and good chances at that, despite only having a miserly amount of possession. Ok, we wasted them, and a number of our forward line are perhaps guilty of trying too hard at the moment, but the goals are there for us to take them when we finally discover our finishing mojos.

We looked solid defensively against the best forward line the world has ever seen. Ok, we threw it away with a moment of madness in the 71st minute, but we proved that we can mix it with the best if we can just keep our concentration for that little bit longer.

We saw that Coquelin and Ramsey can work as a stable, and moreover disciplined, base at midfield, that Welbeck offers a viable alternative to Giroud especially once he’s back to full fitness, and we saw that in Petr Cech, we continue to have arguably the best keeper in the league.

In short, we saw that if we can pull ourselves together for Sunday’s clash, we can very easily take three points, and set ourselves on the road to recovery.

We’ve got 12 league games to go with every chance of winning the title, we’re still in the FA Cup with a relatively favourable route into the semi-finals at Wembley, and we are still hanging on in the Champions League, however desperately, by the skin of our teeth.

Each and every one of those games is winnable, if only we can dial back into that winning feeling, and rediscover some semblance of form.

If we beat Manchester United, we beat Swansea, we beat Spurs, we beat Hull, and we beat Watford between now and 16th March, it’s a tough ask, of course. But if we can manage it, and perhaps nick an early goal, you just never know what can happen. (I mean, we do: we’ll still manage to give another sloppy goal away somewhere down the line, but a girl can dream!)

Picking up momentum

Every run has to start somewhere, and Arsène has got to get our players to focus on the 70 minutes they played to near perfection on Tuesday.

He’s got to get them to pick up on Sunday where they left off when they suddenly decided that actually this ten-men-behind-the-ball tactic was far too boring, and handed Barcelona the very counter attacking opportunity that they’d so effectively blocked all night to that point.

And he’s got to get them to realise that this season is there for the taking, if they could only start making the difference with those small margins that simply aren’t going for us at the moment.

Starting Sunday.