Harry Maguire is set to become the world's most expensive defender, after Manchester United's £80m bid for the centre-back was accepted by Leicester.
United's pursuit of the England international has run throughout the summer but - despite competition from rivals Manchester City - United have got their man.
Here, we answer the key questions around the move - including what Maguire's arrival means for the other defenders at Old Trafford and what other business they have to do before the window closes…
Why were Manchester United prepared to pay a record fee to land Maguire?
"It's an awful lot of money but they know there's a premium," said Sky Sports News reporter James Cooper.
"I think Eric Bailly's injury has certainly concentrated minds. With Phil Jones, Chris Smalling, Victor Lindelof and Axel Tuanzebe, there's plenty of experience but Harry Maguire has always been United's No 1 target and I think some credit goes to United for sticking to their guns.
"They weren't going to go to £85m, £90m. They had a clear fee in their mind they were going to go to. But he was the only signing in the centre-back position that they were looking to.
"It was suggested to me a few days ago that were they not to get Maguire they might leave it until next summer but clearly they've gone for it now.
"Maguire was top of Solskjaer's list and the manager has been clear on his targets and he wasn't just going to fill a position and bring in a body."
In fact, Manchester United looked to bring Maguire to the club last summer, explains Sky Sports News reporter Kaveh Solhekol, while centre-back has been a problem position at Old Trafford for several seasons.
"If you're a Manchester United supporter this is fantastic news," he said. "United have been trying to sign a world-class centre-back for a very, very long time.
"Jose Mourinho tried to sign Harry Maguire last summer on the back of his performances at the World Cup for England. The move didn't happen then - he signed a new contract with Leicester City last summer. But there was an understanding - a gentleman's agreement - that he'd be allowed to leave this summer if a suitable offer came in.
"That suitable offer has now come in. The fee has been agreed and the deal should be agreed very quickly."
So United were keen on Maguire - but what attracted him to United?
Premier League champions Manchester City were also interested in signing Maguire but the defender's preference was always with United.
"Harry Maguire has finally got the move he wanted," said Solhekol.
"We've been close to Harry Maguire all the way through this summer and our understanding was he really, really wanted to move to Manchester United.
"It was his dream move. We told you he wanted to follow in the footsteps of players like Nemanja Vidic and Rio Ferdinand and his dream is about to come true."
What's the reaction been at Manchester United to news their bid was accepted?
Manchester United have had to sit back and watch Manchester City clinch back-to-back Premier League titles but Cooper says there is satisfaction at Old Trafford that they were able to trump their neighbours and beat them to Maguire's signature.
"There's a delight within the corridors of power at Old Trafford that they've fought off Manchester City," said Cooper.
"Yes, they've had to spend big to do it but that they've got someone with proven Premier League experience, who's done well on the international scale and who will bring stability and a lot of nous to a defence that needs restructuring.
"With David de Gea signing a new deal too, it really solidifies things at the back."
So what will Manchester United's defence look like against Chelsea on the opening weekend?
Maguire has featured in Leicester's pre-season and is primed and ready for Premier League action next weekend. And Cooper believes he could slot in beside Victor Lindelof at the heart of United's defence.
"Alongside someone like Lindelof, there are the seeds of a potential partnership," said Cooper.
"It'll be interesting to see if United allow Tuanzebe to go out on loan now - he certainly impressed on the tour. Jones and Smalling have recently signed new deals so there are plenty of options.
"We might see the best from Luke Shaw in that defence with Maguire and Aaron Wan-Bissaka has been fantastic in pre-season. He's impressed a lot of people with his robust tackling and attacking attitude.
"With this mobility, agility and fitness, they're looking a different proposition defensively.
"It looks like it will be a 4-2-3-1 formation this season and with two sitting deep - perhaps Paul Pogba and Nemanja Matic - it will give extra stability to that defence and allow a bit of a settling-in period for Maguire.
"But it'll certainly be a baptism of fire - a potential debut against Chelsea on Super Sunday."
What more business do we expect Manchester United to do before the transfer window closes?
With Maguire signed, Manchester United's focus is now likely to turn to the other end of the pitch, where a potential swap deal involving Romelu Lukaku and Juventus' Paulo Dybala on the cards.
"Dybala is the one Manchester United fans want," said Solhekol. "That would just be a perfect summer for United if they were to get him.
"It still rests on Dybala; whether he wants to come to Manchester United or not. Our colleagues in Sky in Italy at the moment say he would prefer to stay at Juventus. But if Juventus make it clear to him he doesn't have a future at Juventus then I think he would come to United.
"But it's proving difficult to convince him to come to United from Juventus because at Juventus he has Champions League football - and he won't have that if he comes to United."
How will Leicester respond to Maguire's sale?
Maguire's sale could set off a domino effect, with Leicester now needing to bring in a centre-back to replace their top defender.
"The timing of this deal is interesting," said Solhekol. "There are six days to go in the window and with this deal done, it gives Leicester time to sign a replacement.
"Brendan Rodgers - somebody we've been speaking to regularly on Sky Sports News - has made it clear he's got contingency plans. His contingency plans are likely to include players like James Tarkowski at Burnley, there's also been talk of Lewis Dunk at Brighton. Of course, Brighton have signed Adam Webster from Bristol City as well.
"I think Leicester will move very quickly in the transfer window to buy a centre back. The only slight issue they might have is selling clubs will now know that Leicester have £80m in the bank. So when they go knocking on the doors of other clubs trying to find a central defender I think the prices they'll be quoted will be going up just a little bit."