The Gunners are seeking what would be a record 13th triumph in the competition, moving them ahead of Manchester United in that regard, while City - also out of the Premier League title picture - are on course for a sixth success.
Not since 1995-96, the season before boss Arsene Wenger took charge of the club, have Arsenal finished outside of the Premier League's top four. With just a month of the campaign left to go, though, that laudable run appears increasingly likely to be coming to an end.
The Gunners trail fourth-placed City by seven points in the race for European football, while Man United are also better placed three points further ahead, meaning that the FA Cup has become the be all and end all for Wenger in his 21st season at the helm.
While the Frenchman has relied on the competition to appease supporters in the recent past, going all the way twice in the last three years to keep his trophy count ticking along following a prolonged hiatus, this time around feels different due to the sheer disappointment of Arsenal's league form in 2016-17.
The caveat to all this, and something which Wenger will no doubt have pointed out when holding discussions over his future, is that Arsenal are only one point worse off than at this stage 12 months ago. Then, they were third and on their way to finishing behind only champions Leicester City; now, they occupy sixth spot and need a giant helping hand to qualify for European football's elite competition.
It could be argued that the North London outfit are better off without the Champions League, having crashed out at the last-16 stage for seven years running, although qualifying for more than two decades straight is essentially the one constant that has kept Wenger in the job for so long - the argument that the 'Wenger Out' camp cannot truly argue against.
Now Wenger has a big chance to collect a ninth English domestic honour in a competition that he has grown to love down the years, with victory against City this weekend potentially enough for confirmation to be given of a new two-year deal being signed, even if he has recently endured the worst run of results in his long-running spell in charge of the club.
A poor return of three wins in 10, including victories over two non-league clubs in rounds five and six of the FA Cup, has since become five in 13 for the Gunners, but all eggs are looking increasingly likely to be in one basket as far as Wenger is concerned.
The good news for Wenger is that he does not tend to lose matches at the new Wembley, having gone six without losing here to lift the famous cup in 2014, 2015 and now potentially in 2017. A failure to complete the trio of successes since the turn of the decade, however, and Wenger's time may very well be up.
Recent form in FA Cup: WLWWWW
Recent form (all competitions): WLDWLW
While Arsenal boast impressive pedigree in the FA Cup, particularly in recent years, Man City have gone all the way just once since the end of the 1960s - 2010-11, when overcoming Manchester United and Stoke City in the semi-final and final respectively.
That was seen as a pivotal moment in the Citizens' history, acting as the precursor to the following year's maiden Premier League title success, but it is arguable that they have not truly pushed on since - not in the manner many would have expected, at least.
Another top-flight crown followed in 2014, granted, and two League Cups were also added to the trophy cabinet under Manuel Pellegrini, but the club's owners were clearly gearing up for more dominance - hence the arrival of super-coach Pep Guardiola last summer.
The Catalan's first season in English football has not quite gone to plan on the whole, with City limping out of the Champions League at the first knockout-stage hurdle and drifting well out of the title picture, yet a third-place finish and success in the FA Cup will give supporters all the more reason to remain optimistic ahead of a huge summer for the club.
It is clear that Guardiola is not entirely happy with his current group of players, many of whom are set to see their contracts expire in a little over a month's time, and the former Barcelona and Bayern Munich boss will be under far more pressure to impress when August rolls around.
City are firmly back on track in the league thanks to successive wins, at least, seeing off Southampton 3-0 last time out in what was arguably their finest all-round away display of the campaign so far - no coincidence that influential skipper Vincent Kompany was back for that one.
This is now a truly pivotal week for Guardiola and his charges, though, as they follow up Sunday's cup semi-final with a meeting against Man United in the league, knowing that a positive result over their neighbours could well make sure of a top-four finish.
Guardiola will not be looking beyond this weekend for now, and of the two sides it is City who have had the tougher run to this stage, beating three Premier League sides compared to Arsenal's one - a 5-0 thumping of Southampton in round four the standout result of the competition as far as the Gunners are concerned.
Recent form in FA Cup: LWWDWW
Recent form (all competitions): LDDLWW
Arsenal will definitely be without Lucas Perez and Shkodran Mustafi once again this weekend, while Danny Welbeck - the scorer of an impressive brace against the Saints in the early rounds - is to undergo a late fitness test on a toe injury.
Wenger surprised many by reverting to a three-man defence in Monday's 2-1 win over Middlesbrough, something that he has not done from the off in some 20 years, and there are suggestions that he could extend that experiment until the season's end.
Should that be the case, Wenger's biggest call will come in the right wing-back slot, where Hector Bellerin is pushing for a recall after being left out last week following a loss of confidence.
Man City may have Gabriel Jesus back in their ranks well ahead of schedule, meanwhile, as the £27m striker has recovered from a fractured metatarsal inside just two months and will likely take up a place on the bench.
Twenty-nine goal striker Sergio Aguero is the obvious choice to continue leading the line in a City side packed with attacking talent, with Yaya Toure - the hero here for City during their last run to the final - possibly missing out to make room for others.
In goal, Claudio Bravo appears to have wrestled back the number-one shirt from Wilfredo Caballero in time for this huge match, but there will be no John Stones at Wembley as he continues to recover from injury.
Arsenal possible starting lineup:
Cech; Gabriel, Koscielny, Holding; Oxlade-Chamberlain, Ramsey, Xhaka, Monreal; Ozil, Sanchez; Giroud
Manchester City possible starting lineup:
Bravo; Navas, Otamendi, Kompany, Clichy; Fernandinho; Sane, Silva, De Bruyne, Sterling; Aguero
Head To Head
Three of the last six meetings between these two sides have finished 2-2, including the most recent encounter at the Emirates Stadium just three weeks ago.
Arsenal have won two of the other three matches in that run, while City have just the one victory in their last eight encounters with the Gunners overall.
We say: Arsenal 1-2 Manchester City
Is it too much to suggest that this is a must-win match for both sides? Perhaps more so in the Gunners' case, with Champions League football looking an unlikely safety net for Wenger to fall back on this time, but this will be a very tough task for his side. Guardiola has grown to love Wembley, both in its former and current guise after lifting the European Cup here as a player and coach, with another famous win at the home of English football this weekend enough to keep him on track for silverware in his first campaign on these shores.