It is fair to say that during his time as Arsenal boss Arsene Wenger may have never come up against a more formidable opponent on the pitch than Roy Keane. The infamous battles between the Manchester United captain and Arsenal's Patrick Vieira are well documented, and are among the most fondly remembered in the Premier League era.
This weekend however will see Wenger going head-to-head with Keane in a rather different capacity. Keane is now assistant manager for both the Republic of Ireland and Aston Villa - and will be assisting Paul Lambert at Villa Park this weekend for the visit of Arsenal.
Keane, a long term friend of Lambert's, took up his first role in club football since leaving his role as Ipswich Town boss in 2011 in order to become Villa assistant. It came after a disappointing spell a Portman Road - which had followed two good years at Sunderland.
But Wenger believes that taking a step back into the number two position should not be something Keane should be ashamed of.
He told his Friday morning press conference:
"You find your place where you're happy and that's the most important thing in life. If he's happy there, why not? He's in football - he's involved without maybe being always questioned about everything. He can have a positive influence. They have played four games but he can of course have a positive influence."
That positive influence is clear to see. Villa are sitting pretty in second place on 10 points and are unbeaten in the Premier League - with Keane's presence being dubbed a serious factor in their excellent start to 2014-15.