David Moyes has moved Eliaquim Mangala to the top of his January wish-list after returning from a scouting mission, reports the Daily Mirror.
The powerful Porto defender wasn't at his best in Wednesday night's clash against Atletico Madrid, losing 2-0 and crashing out of the Champions League in the process.
Mangala still did enough to convince the Manchester United manager on his ability, who is now plotting a £15m bid to secure the player ahead of rivals Manchester City and Chelsea.
Manuel Pellegrini and Jose Mourinho have both been long-term admirers of the French international and were both linked with January moves as they look to strengthen their options at the back.
Pellegrini has growing concerns that his captain Vincent Kompany will continue to struggle with injury and, with Javi Garcia having to fill in at centre-back, it seems no replacements is currently available at the Etihad.
Mourinho, on the other hand, is looking for a long-term replacement for John Terry as the former-Porto manager refuses to be convinced that David Luiz can fulfil the role.
But both teams now face competition from the Premier League champions as Moyes, like Mourinho, is eyeing long term options to replace to ageing Nemanja Vidic and Rio Ferdinand.
Chris Smalling and Jonny Evans have both failed to impress when filling in for the veterans this season while Phil Jones is still needed to reinforce the midfield.
Mangala currently has a release clause of £40m, but the Red Devils are confident of sealing his signature for significantly less in the new year because he is cup-tied for European competition.