It is the big one, certainly for Mikel Arteta.
Arsenal take on his former employers Manchester City on Wednesday night.
Arteta spent three years as assistant manager to Pep Guardiola at City and will now face off against them as head coach of Arsenal.
It's a big one for the fans as well, who know that victory will take the Gunners above north London rivals in the Premier League table.
After victory over West Ham on Saturday, who will Arteta choose to get the result against the Premier League champions?
We asked our Arsenal writers to name the team they would play if they were the boss.
Art De Roche - Arsenal writer
Now must be the time for Ainsley Maitland-Niles to return. Learning that Hector Bellerin was playing with a groin tear only makes his absence from the side more confusing. Sokratis as done relatively well at right-back but Maitland-Niles is much more comfortable in that role and should be starting there.
Although Kieran Tierney is back in full training, coming back against Manchester City may be too tough an ask. Rather than throwing him in at the deep end, holding him for later would be better.
Dani Ceballos and Granit Xhaka remain as the double-pivot. Despite Ceballos' improvement it would be nice to see Xhaka assume more responsibility on the ball as he did early on under Mikel Arteta.
Pierre-Emerick Aubameyang would remain on the left as Eddie Nketiah stays down the middle. Alexandre Lacazette could have a shout to start but having Nketiah buzzing around Fernandinho and Nicolas Otamendi may suit Arsenal better from the start.
De Roche's team: Leno; Maitland-Niles, Luiz, Mari, Saka; Ceballos, Xhaka; Pepe, Ozil, Aubameyang; Nketiah.
James Benge - Senior Arsenal writer
Will Mikel Arteta's usual gameplan work when his team scarcely have the ball? You suspect not and that surely ought to inform how Arsenal line up at Manchester City.
It was notable that Eddie Nketiah drew praise from Arteta not just for his goalscoring exploits against Portsmouth but for "the rhythm that goes into pressing", it may well be that he and Joe Willock earn a chance to set the tempo from the front and probe for errors from a backline that will be without Aymeric Laporte.
At the back there is an intriguing battle to be had between Shkodran Mustafi and Pablo Mari for the right to partner David Luiz in central defence. If the German is fit then his performances have been sufficiently impressive to earn a starting spot.
Benge's team: Leno; Bellerin, Mustafi, Luiz, Saka; Ceballos, Xhaka; Nelson, Willock, Aubameyang; Nketiah.
Now it's time for you to have your say.
You can pick the team you would play if you were the manager using our interactive gadget below.
Mikel Arteta has some big decisions to make, but what would you do?
Share your teams with us on Twitter (@ArsenalFC_FL) and Facebook (AFCFootball.London).
