If Arsenal fans are deflated that they didnt ultimately get that x-factor star, its a feeling shared within the squad. Some of them agree they are thin in that area, especially after losing the popular Gabriel Martinelli. But its encouraging in other ways. That's how competitive they now are. They want players in there who will help them, as Chelsea might say, to win it all.This weekend, mind, football is now doing what it does and throwing up one of those little narrative twists. In the first match after a highly debated window, Arsenal face the left-sided attacker they could have had and now need; heres what you could have won with.Morgan Rogers has already been adapting to Chelsea admirably, linking up so excitingly with the rest of that attack. Arsenal sources would ultimately say that, as good as Rogers in, they didnt feel he was worth the price that Chelsea eventually paid. Behind him, however, Chelsea might be looking enviously at Arsenals midfield.Arsenal host Chelsea on Sunday in an early meeting of the champions and the potential challenger in an unpredictable season (Getty)Where Xabi Alonso's squad is suddenly thin in that area, after the collapse of the Lamine Camara deal, Mikel Arteta has arguably the best midfield in world football. Only Barcelona probably trump Arsenals options.The difference could prove the winning of the game and maybe, eventually, the title?Arsenal and Chelsea are already sizing each other up.Thats something that the London rivals have done a lot since the Stamford Bridge side became newly cosmopolitan from the mid-1990s. The Roman Abramovich takeover then fired a rivalry that may not have had the historic depth of either Arsenal-Tottenham or even Chelsea-Tottenham, but it has had real edge. Just remember Jose Mourinho and Arsene Wenger.But Arsenal and Chelseas rivalary has never had the edge of a title race. Despite both enjoying two of their best ever teams at the same time around 2000-06, they never fully went at it. Yes, they finished as the top two in 2003-04 and 2004-05 over that period, but they werent proper title races. They were processions.Some of this shouldnt be a surprise, given the history. There havent actually been any proper London title races at all. The only other London top two was Chelsea-Tottenham in 2016-17, which didnt feel a full race either.That may seem anomalous, but a significant part of that is because of the norths long dominance over the English game, having formed its initial heartland. No London club even won the title until Arsenal until 1931, a full 44 years after the leagues foundation. They followed with another five before Spurs finally became Londons second champions in 1951 and Chelsea their third in 1955.Arsenal really offered the capitals only dynasties until this millennium. If they were to finally go at it with Chelsea, it would be a historic first.There was venom in the clashes between Wengers Arsenal and Mourinhos Chelsea but without a proper race for the titleThe looming presence of a newly bolstered Manchester City of course changes the equation, but also serves to emphasise the games evolving structural forces.A first ever London title race would be an inevitable consequence of the profound commercialisation over those last 30 years, where private capital has naturally been drawn to a mega-city with established football brands like London.The ownerships of Arsenal and Chelsea represent different forms of this, that have influenced the very football they play, too.The Kroenkes are classic American patriarch family wealth, and have consciously looked to allow Arteta the stability to build.Chelseas ownership are a consortium led by Clearlake, who were the first major private equity owners in football, and almost act as disruptors. You only have to look at how they have diverted from a lot of footballs norms, from squad-building to transfers and even the mechanisms they have used to adhere to regulations.Morgan Rogers has added the x-factor to Chelseas attack in a summer where Arsenal missed out on their top targets (Getty)It isnt a coincidence that difference is going to be seen in the football this Sunday.Arsenal are a picture of control, and almost too much control. Arteta has gradually been allowed to develop the team to this point, the manager all powerful, so every signing feels like another considered piece.Chelsea have so far played two matches when they didnt have control at all. Alonso has suddenly been dropped in as the new coaching solution, charged with imposing a system on a never-ending turnover of players. They will of course evolve, especially without European football, but its still early.Chelsea would say that key players like Cole Palmer - and indeed Rogers - are planned pieces in the way Arsenals are, but its undeniable thats with a lot of change around them.Mikel Artetas attack looks lighter than last season but his midfield and defence are stronger than anyone elses (PA)That change has now left them with a thin midfield, that both Fulham and Brighton already outmanoeuvred in matches that shouldnt have been as close as they became. Chelsea couldnt seize either match.At the end that matters most, however, that chaos arguably better served this stellar attack. Palmer was constantly able to drop into dangerous positions, taking Alonsos desired transitions on to some devastating attacks.If Chelsea cant control 90 minutes, they can still kill you in nine seconds. Arsenal know they cant make many mistakes. Thats now a new message with Arteta. His entire philosophy is ultimately about cutting out mistakes altogether, about complete control.It has been the foundation of three title challenges, and one victory. Now, an opposing approach, in an opposite corner of London, may a pose a title challenge the English game has oddly lacked.