Rewind a few months and conventional wisdom was that Arsenal required three players to bolster the spine of the side and become genuine title challengers: a centre-back, a central midfielder and a centre forward.

But Arsene Wenger has rarely been a man to heed conventional wisdom. Stubbornness is ingrained, stability institutionalised. He made Arsenal the only club in Europe’s top five leagues not to sign an outfield player in the summer of 2015.

When he recruited Granit Xhaka in May, it seemed times were changing. When he went three months without adding anyone else apart from youngsters, it looked like Wenger was being Wenger, almost deliberately provoking his critics with money-saving inaction. When he begrudgingly and belatedly bought Shkodran Mustafi and Lucas Perez at the end of August, it appeared he had adopted outsiders’ more expensive approach.

And yet when Arsenal head to Old Trafford on Saturday, it will be with a blend of old and new theories. Mustafi has established himself in the centre of the defence, proving an upgrade on the injured Per Mertesacker and the benched Gabriel. Xhaka may start in the middle of midfield, especially if Santi Cazorla is ruled out. But Perez will not lead the line, and not just because an ankle injury that will keep him out until December. He has only played 87 minutes of Premier League football, failing to score.

And Wenger, in Wenger-esque fashion, has found the answer within instead. He has revamped his attack without investment and with a quintessential quartet who, between them, highlight virtually every aspect of his management.

On the left, there is the youth prospect he has promoted, in Alex Iwobi. On the right, there is the player Wenger has persevered with when many thought he should have sold, the example of continuity at the Emirates Stadium that is Theo Walcott. Operating as the No. 10 is the misunderstood talent sometimes branded a luxury player, in Mesut Ozil. And operating as the striker is the footballer who some would not deem a centre-forward at all: Alexis Sanchez.

The Chilean’s closest comparison may seem Roberto Firmino, another all-action South American winger pressed into service as a striker of sorts in England, but he taps into a deeper tradition at Arsenal. Thierry Henry and Robin van Persie were perceived as wingers when Wenger signed them: the Dutchman spent much of his early years at the club on the flanks. But there were summers when Wenger didn’t sign strikers – in 2006, when Henry left, and in 2009, when Emmanuel Adebayor was sold – and he used them to usher Van Persie into a more central role.

Sanchez is the striker who isn’t always in the striker’s spot. Rather the duties are shared. That is apparent in the fact Walcott is the joint top scorer and he, as much as the Chilean, uses his pace to sprint in behind defences. There is even a role reversal with Ozil at times: Sanchez dropping into midfield while the German, showing a long disguised ruthlessness, has made penetrative vertical runs.

They are not all at the same standard and most do not yet boast anything like the same achievements, but in their fluency and fluidity, there are echoes of Wenger’s finest front four, when Henry veered out to the left, Dennis Bergkamp retreated into midfield and Robert Pires and Freddie Ljungberg cut in from the flanks to score. Like their modern-day counterparts, they did not have fixed positions. 

But there is another element that is typically Wenger. Much of the striking debate at the Emirates Stadium in recent years has revolved around Olivier Giroud. Unfairly maligned by his critics, the possessor of a better scoring record than many appreciate, the Frenchman may not have been quite good enough to win Arsenal the league. But nor were the other strikers who Arsenal could afford and entice.

Hence the need to search for internal solutions, to convert Sanchez and form a new forward line where it feels Arsenal’s outstanding attacker has been asked to sacrifice himself by adopting a position that is not his best. Yet Giroud is emblematic of Wenger’s Arsenal, where issues rarely disappear. When in the team, many wonder if he should be dropped. When out of it, he mounts a case to start. 

He has been downgraded to Plan B. Should Sanchez’s hamstring problem or international travel prevent his participation against Manchester United, a recall may beckon. The like-for-like replacements, the winger-strikers Perez and Danny Welbeck, are injured. Walcott spent years flirting with being a striker only to decide he isn’t one after all.

So, once again, Wenger could enter a potentially season-defining game with Giroud in attack. It would have a familiar feel, but then much in the Arsenal attack bears similarities with the past.