Chelsea will face competition from Manchester United for Porto defender Eliaquim Mangala. Blues boss Jose Mourinho is looking for defensive reinforcements after the club agreed to sell David Luiz to Paris Saint Germain for an astonishing 50m. Mangala was the subject of a big money bid from Manchester City in January and the Citizens are likely to renew their interest this summer, along with Manchester United who are desperate for top quality defenders after losing Nemanja Vidic and Rio Ferdinand. Mourinho, though, believes he holds the upper hand with his Porto connections. The Portuguese only has Gary Cahill and the ageing John Terry as his senior centre-backs and needs competition for the pair, as well as someone to eventually take over from Terry when he finally retires. Mangala is still only 23 and has shown his worth over three seasons at Porto and is understood to be ready for a new challenge, European football sources have revealed.