Mikel Arteta has a clear message to send after Arsenal’s incident-filled draw with Atletico Madrid

Mikel Arteta fumed about that. “After watching the second penalty decision getting overturned, [I’m] extremely disappointed and annoyed because it’s against the rules,” he said.

"What I am fuming with is the decision to overturn Eze's penalty. It's not a clear and obvious error. It changes the course of the game. We are all fuming with that."

Diego Simeone was of course right there in amongst it. Everything else seemed open to interpretation, including the very state of this game.

Arsenal could be encouraged but frustrated, if also relieved from one or two occasions. Atletico could be proud, and roused. And if this tie was always going to be compared unfavourably to Tuesday, it did ebb and flow in its own absorbing way.

That’s the thing about this stage of the competition. Obviously you would prefer the spectacle of Paris, but the very tension of being so close to the club game’s greatest fixture guarantees every moment is enthralling in its way.

That had different effects at different times.

Arsenal may well rue the fact they didn’t press home when they were properly on top by half-time. At 1-0 up after Viktor Gyokeres’ penalty, they looked like they could get two or three. There was always that suggestion of more, that they could have done more.

Simeone even seemed so concerned by it that he went to five at the back.

Ben White gave away a penalty when the ball struck his arm in the box (Getty)

That ended up being a ploy of its own. It stretched the game and gave Julian Alvarez and - especially - Antoine Griezmann the space to finally play.

The French star, no doubt conscious that next week’s return leg could be his last ever match in the Champions League, played like he was determined to avoid it.

He suddenly just lifted it, and lifted his team.

The only issue was that he lifted some of his efforts that bit too much, too. In that one frenetic second-half flurry, two brilliantly improvised efforts narrowly missed.

That was still the source of Atletico’s equaliser, as the ball was being beaten around so much it eventually hit a hand.

That was kind of the story of the game. It was played in those margins, when there could have been more.

Could Arsenal regret that? They at least have the grand occasion of a home semi-final second leg to come.

The big question might be over whether Atletico can actually raise it. They were actually remarkably poor in the first half, with Arsenal in almost full control. You could suddenly very easily see why they are fourth in La Liga with so few victories of late. They had so little, with even their admittedly stellar attack unable to get into the game.

And then, whatever happened at half-time, Simeone dug in and found something. The spirit had transformed.

There were shades of the old Atletico there, the knife between the teeth, the strong challenges where they needed to be. There was a new menace about counters.

Ademola Lookman had enough openings of his own, but David Raya had yet another assured display. The one pity, in perhaps the most decisive moment of the tie, was that Arsenal target Alvarez had to go off injured.

It was one of a few factors that sapped Atletico of that energy, forcing them back. Another fatigue. As with their less fevered start to the first half, they naturally couldn’t keep up that energy.

Julian Alvarez equalised by scoring from the penalty spot (Getty)

Arsenal had more of the play and the attacking towards the end. They looked the likelier winners at that point.

They might have been exactly that had referee Danny Makkelie not overturned the Eze decision.

The playmaker did seem to go down easy, but there was contact, and that was probably just enough to make the eventual overturn a surprise. It was in-keeping with the previous two in allowing debate.

Hancko was maybe fortunate to get away with a second. He had been responsible for the opener, after a risky challenge on Gyokeres. The striker again looked like he maximised contact, but it was there.

Gyokeres took advantage, and took it brilliantly. If he has received criticism for aspects of his forward play this season - and he had a much better game here - there’s no doubting his ability to absolutely smash it from a clear position.

Eberechi Eze thought he'd won a penalty before the decision was overturned by VAR (Getty)

With Ben White’s handball, it might have felt very harsh in the Premier League, but not in Europe. Those are the rules - or at least the interpretation of the rules.

After the penalty given to Bayern Munich against Paris Saint-Germain, it was obvious. As Alvarez stepped up, it looked like Raya - and maybe a few others - expected a Panenka. The forward instead hammered it.

He found that bit of spirit. So did Atletico.

It feels like the big question in this semi-final is whether they can raise it again, in much more testing circumstances.

Arsenal still actually have a job to do, after an awkward Saturday home match against Fulham. The time is quickly coming for debates to end and everything to become clear.

Arteta must hammer that message home.