Ever since Bruno Fernandes arrived at Manchester United in a £68million deal in January, there has been a conundrum Ole Gunnar Solskjaer has struggled to deal with.
With both Fernandes and £89m man Paul Pogba both vying for the same spot in United's midfield, it is near-on impossible for Solskjaer to please both - as has been evident from recent line-ups.
But add in the summer acquisition of £40m Donny van de Beek, another creative midfielder, and that selection headache becomes a full-on migraine. One that has cost the club a combined £197m in transfer fees.
Bruno Fernandes has become Manchester United's main spark for creativity in the middle
Paul Pogba has played a limited role in recent matches but started against RB Leipzig this week
If both Pogba and Fernandes are included in the starting line-up, there is very little protection for the United backline, which was highlighted by their 6-1 drubbing against Tottenham in the Premier League.
Hence why Solskjaer opted to deploy his No 1 creative star Fernandes in front of both Fred and Scott McTominay to shore up United's defence for crunch matches against the likes of PSG and Chelsea.
And following the 0-0 draw against Chelsea, as Pogba once again came on as a late substitute, former Liverpool defender turned pundit Jamie Carragher made the assertion that the Frenchman and Fernandes simply cannot function in the same team together.
Carragher questioned why on earth United had signed Van de Beek too.
He said: 'I actually admire (Ole Gunnar) Solskjaer for putting Pogba on the bench.
'I said a few weeks ago after the Crystal Palace game, Fernandes and Pogba is not a midfield that can play together and never will be.
'Van de Beek, I don't understand the signing, I really don't get it, how he was ever going to play or where he's going to fit in.
'As soon as he signed I thought he plays No 10, Fernandes plays there, Pogba can play there.
'It's actually better for the team having Fred and McTominay in there. But having Fred and McTominay is not good enough for Manchester United to win the league either.
'The problem for me is Paul Pogba, I've said it for a long time. I'm with Gary (Neville), Fernandes is the man for that No 10 position but I don't know how Ole can not pick a £90m signing in Pogba, it's difficult for a manager, so at some stage he will get back into the team.'
Jamie Carragher is adamant that United cannot function with Pogba and Fernandes together
That time came on Wednesday night, as Solskjaer decided to rest Fernandes for the Champions League encounter with RB Leipzig and instead start Pogba and Van de Beek as part of a midfield diamond.
It worked a treat, with the Dutchman looking bright at the tip of the formation, Pogba pulling the strings and Nemanja Matic and Fred keeping things secure in an emphatic 5-0 victory at Old Trafford.
But while the extra options are a nice problem for Solskjaer, keeping his players happy and finding a way on incorporating them into the same starting XI remains an issue he must fix. With over £170m worth of midfield talent on the bench during the bore 0-0 draw with Chelsea, this can't be sustainable in the long run.
The big problem with using both Fernandes and Pogba is that there is a big chance that the opposition can overrun a weak midfield. With a lack of defensive discipline, teams could run riot just like Tottenham did at Old Trafford a few weeks ago. They picked them to pieces and United's concerns were there for all to see.
Donny van de Beek started at the top of a midfield diamond in the 5-0 win over RB Leipzig
But herein lies another puzzle. It's tempting to play the pair together against less formidable sides. Pogba and Fernandes can pick apart teams with ease thanks to their creativity, guile and power.
When the pair have played together since Fernandes' arrival, United have won seven matches, drawn just two and lost two.
They have scored 26 goals in the 11 matches, while managing a whopping 132 shots. So there certainly will never be a creativity issue.
But defensively, United's worries are obvious. During those 11 matches, the Red Devils have conceded 16 goals and faced 130 shots.
However, when Fernandes has started on his own with more protection behind him, United have looked far more assured at the back - conceding just three times in eight matches.