While that deal was a long time in the making, Ighalo's arrival came as a surprise as United's exhaustive search for a new striker landed on the Shanghai Shenhua man.
The 30-year-old has joined on a short-term loan deal until the end of the season, while United have the option to make that move permanent in the summer.
Here, Sports Mole looks at how Ole Gunnar Solskjaer could line his side up following the deadline-day business.
However, a fully-fit squad looks like an attractive proposition for United fans following their January business, with Fernandes slotting directly behind fellow new arrival Ighalo.
Fernandes has scored 48 goals over the past season-and-a-half in addition to creating 20 more in the league, so his presence in attacking midfield looks likely to increase United's goal threat.
Ighalo also has a proven goalscoring record in the Premier League from his time with Watford, where he netted 39 times in 99 appearances for the Hornets.
Rashford remains United's main goal threat when fit and he would be a shoo-in to start on the left, but Ighalo's presence could force Anthony Martial out to the right rather than his preferred central role, which he has occupied for much of the current campaign.
The likes of Daniel James, Andreas Pereira and Juan Mata would see their first-team chances hurt by that, while further back Pogba and McTominay are likely to be the first-choice midfield pairing in a fully-fit squad despite the good form of Fred and Nemanja Matic in their absence.