Every club needs a Daniel Nii Tackie Mensah Welbeck…

Unai Emery is not a magician. Jurgen Klopp could manage it with James Milner, while Pep Guardiola did a fine job with Fabian Delph. But the Arsenal head coach could not quite pull off the same trick. When Guardiola insisted that “midfield players can play anywhere”, he did not have Granit Xhaka in mind at left-back.

At one point, nor did Emery. His initial response to an injury crisis in the position was rather different. “Right winger, left winger, striker, and also yesterday he worked with us at left-back – his performance was good!” he said of Danny Welbeck in August. “I like this spirit. To help positions across the team with positive spirit.”

It was that same positive spirit that brought Arsenal an 11th consecutive victory, one of the most hard-earned yet in Portugal. Sporting were not particularly impressive, but then neither were the Gunners. To win under such circumstances is quite the achievement.

Once again, Emery got his starting line-up wrong. Once again, he tinkered slightly with it throughout the game. Once again, it garnered the desired result. Arsenal have now converted eight of their half-time draws into wins this season. This is no longer a coincidence.

This time, it was the introduction of Lucas Torreira that completely changed the complexion of this match. Arsenal started with a midfield trio of Matteo Guendouzi, Aaron Ramsey and Mohamed Elneny, and understandably struggled to control the tempo. Guendouzi did his absolute best with precious little help, the teenager forced into the role of designated driver as his two more experienced teammates ambled through. The 19-year-old made nine more forward passes than Ramsey and Elneny combined in the first half.

Yet he could only do so much. It was only when Torreira replaced Elneny that Arsenal found a foothold. They finally had a reliable base to work from, a midfielder capable of playing quick passes between the lines instead of six-yard balls sideways.

His impact is indelible. Arsenal have now played 497 minutes without him this season, scoring nine goals and conceding ten. In 673 minutes with him on the pitch, they have scored 24 goals and conceded four. If any player is undroppable under Emery, it is the boy from Uruguay.

It was his pass that so unsettled the Sporting defence, forcing the sort of mistake from Sebastian Coates that Liverpool supporters would have greeted like an old friend. The ball was slightly overhit, evading the initial target of Pierre-Emerick Aubameyang before falling into Welbeck’s path, but the intent was the important aspect.

And the run and finish was superb, particularly from a player often derided for his abilities as a striker. He has now scored as many goals as Alexandre Lacazette in 293 fewer minutes, and is five goals behind his best scoring season for Arsenal with seven months still to play.

Therein lies the beauty of a player like Welbeck. He is not happy to play second fiddle – no footballer can be – but he is the archetypal squad member. He will not kick up a fuss when he doesn’t feature, and will maximise the times he does. In any team, that is crucial. In a team with strikers as brilliant and as expensive as Arsenal’s, that is priceless.

“I said to him when he arrived with us after the holidays, I want the best performance in his career from this player,” Emery added two months ago, shortly after pitching Welbeck as an auxiliary left-back. Dat Guy is delivering thus far.

Matt Stead