MICHAEL Carrick has faced a lot of very different challenges since taking charge at Middlesbrough but today's is unique - for the man in the opposition dugout, Kieran McKenna, knows Boro's boss inside out, with the pair having "emptied their football brains on to each other" while working together at Manchester United.
It goes without saying, then, that McKenna faces the same challenge as Carrick as Boro take on Ipswich at the Riverside this afternoon: how on earth can they catch the other off guard given they "worked in each other's pockets" at Old Trafford?
Carrick laughed when it was put to him that there must be a temptation to spring a Boro surprise in an attempt to wrong-foot McKenna this afternoon.
"Of course," he smiled.
The problem there for Carrick, however, is the not so small matter of 10 players being unavailable. Regardless of who's missing and how the XI looks, Carrick is relishing the opportunity to take on his former Old Trafford office-mate - who rang the Boro boss for some advice when he was offered the job at Portman Road.
In the two years that have followed, McKenna has established himself as one of the brightest young head coaches in the game - which comes as no surprise whatsoever to Carrick.
From the minute Carrick first saw McKenna as a coach in the Manchester United youth age groups, he knew the now Ipswich boss would go on to have a "terrific career". The pair went on to work alongside each other in the first team coaching set-up at Old Trafford alongside Ole Gunnar Solskjaer and Jose Mourinho, before they both set out on their own managerial careers.
And they've both fared rather well themselves, Carrick so nearly taking Boro to the Premier League last season and McKenna guiding Ipswich to promotion from League One to the Championship, where they've established themselves in the top two and look not just promotion contenders but favourites.
Carrick and McKenna actually first came across each other as players at Tottenham. McKenna was forced to retire early due to a hip injury, while Carrick went on to enjoy an incredible career, winning everything in the game.
And yet despite the modest Boro head coach's glittering CV, he claims he learnt more from McKenna at Old Trafford than the now Ipswich boss did from him.
“He has done an incredible job which I am not surprised about one bit," said Carrick of McKenna.
"I have obviously worked with him over quite a period of time and got to know him and know how good he is, one of the best coaches you could ever hope for really, one of the best I have ever come across.
"He’s got a very good football brain and eye for detail, and his knowledge is just incredible in terms of what he can store and remember. On the grass he’s fantastic as a coach in how he structures his sessions. He’s an all-round top coach. I learned a lot from him having come from very different backgrounds. I came from playing and Kieran has come from coaching from pretty much the start.
"We were actually at Tottenham together – he was in the reserves when I was playing. He got injured and went to coaching. I picked his brains a lot and we ended up learning a bit from each other, though I probably learned more from him than he did me!"
So how do you plan to come up against a manager who you know - and who knows you - so well?
"Look, we have worked in each other’s pockets for so long at United, kind of emptied each other’s football brains on to each other," admitted Carrick.
"There is definitely that. Of course, we evolve and there are different ideas Obviously, you are what you are in terms of principles and I know how he thinks. I am not saying I know what he is going to do on Saturday.
"I would be very silly to think that but I have an idea and he will be exactly the same with me."