Arsenal no longer fear falling short and now have clear sight of immortality | David Hytner

Arsenal fans gathered for a mass welcome for the team bus before the game. Photograph: Jacques Feeney/Offside/Getty Images

It feels like the dream run-in (please read disclaimer in small print) – a little like Arsenal’s draw for the Champions League knockout rounds: Bayer Leverkusen, Sporting Lisbon and Atlético. In other words, no European super-powers. Arsenal earned that, in part, by finishing first in the league phase with eight wins out of eight.

There is the sense of the stars aligning. After all the suffering, particularly from the end of March, all the angst, the mortal fear of falling short, there is greater faith and assurance, a more positive vibe. It has taken hold suddenly because seven days ago, after the first leg against Atlético, the mentality was more akin to that of a siege.

Mikel Arteta railed at the authentically terrible decision to overrule a penalty award that stood to give them a 2-1 lead. The tie ended 1-1, which was a very good result, especially as Arsenal had not been at their best. In the game before that, at home against Newcastle in the league, it was fraught, Arsenal struggling for creativity on their way to a 1-0 win.

Everything changed in the 3-0 victory over Fulham on Saturday – again at the Emirates – with one of the main takeaways being how calm everybody was before and during the game, with the emphasis on the beforehand bit and the early part of proceedings. As against Newcastle, Arsenal scored in the ninth minute, but this time there was no sinking back, no frayed nerves on the pitch or in the stands.

They were remorseless, playing with tempo. They pushed and it did not matter to them that they missed a couple of chances and had a goal disallowed. The certainty was back. It was 3-0 by half-time. Arsenal had scored six goals in their previous eight matches.

It helped that Fulham, whose preparations were affected by a sickness bug, were so poor. But there was an energy about Arsenal, a freshness Arteta noted was down in part to five changes to his starting XI. The biggest boost was the return of Saka after injury. But Riccardo Calafiori’s comeback was significant and then there was Myles Lewis-Skelly in midfield in place of Martín Zubimendi.

Myles Lewis-Skelly returned to the side and proved himself against Fulham and Atlético Madrid. Photograph: Matt Impey/Shutterstock

It has been a difficult second season at senior level for Lewis-Skelly and Arteta has admitted he has been tough on him. The 19-year-old has had a point to prove. Against Fulham then Atlético, he proved it. On a related point, Declan Rice has dropped back into more of a No 6 role – his old position – and showed why he has such strong support to be named as the footballer of the year.

Arsenal took the feelgood factor of the Fulham game and ran with it into Atlético, the added tonic being City’s failure to win at Everton on Monday. The pre-match scenes were orchestrated to inspire the players, especially the mass welcome by the fans for the team bus on the approach into the Emirates, the smoke from red flares adding to the scene. It was not crazily loud or spine-tingling, but it was, nevertheless, a visual treat.

When it was all over, it was Arteta who led a group of players from one end of the pitch to the other, each of them hand in hand, the adrenaline overflowing. It was hard to remember him looking this happy and it was yet another move by him to whip up the crowd, to create positive energy. They have not all worked in recent weeks. For example, the “bring your lunch” address before the home loss to Bournemouth.

But Arteta sticks at it. This is who he is. He called for “no fear, pure fire” before the second leg against Sporting. He wanted players to “define history” against Fulham. Before the second leg with Atlético, he demanded they were ready to “go out there like beasts”.

The scenes in the dressing room after the victory will stay with everyone who witnessed them, including the Los Angeles Rams head coach, Sean McVay. He was a guest at the game and was invited down after. The challenge for Arsenal is to ensure the momentum is inexorable.

“Sometimes you have these moments in the season where it shifts towards you and everyone has full belief that we can do it,” the winger Leandro Trossard said. “That’s how it is at the moment.”