Jose Mourinho has revealed that signing a midfielder will see Manchester United complete "crucial work" in the summer transfer window. The Red Devils have already added three new faces to the squad.

The list includes defender Eric Bailly, striker Zlatan Ibrahimovic and creative player Henrikh Mkhitaryan. The 20-time English champions are hoping to bring Paul Pogba back to Old Trafford.

Pogba left United and joined Juventus on a free transfer in 2012. In Italy, the 23-year-old has developed into one of the star midfielders in Europe, which has seen him attract interest from Manchester United and Real Madrid, reports the Spanish publication El Confidencial.

According to the Guardian, United are preparing a £100m bid in landing the Juventus star this summer. Mourinho remains hopeful that the Red Devils will bring in a midfielder in the current transfer window.

"Then, the market will be open until the 31st of August, and sometimes things happen that you are not expecting, and we have to react," Mourinho said, as quoted by ESPN.

"But our fundamental market is 75% done. And when we sign one midfield player that crucial work will be done."

"I said at the first press conference at Old Trafford, our market has a fundamental part. And that fundamental part is four players: one central defender, one midfielder, one striker, and one creative player. And when we finish that fundamental market we are balanced."

"Maybe today [after defeat to Borussia Dortmund] you don't feel it but no Ibrahimovic, no [Marouane] Fellaini, no [Anthony] Martial, no [Morga] Schneiderlin. So lots of them who are not here yet," the former Chelsea manager added.

United suffered a 4-1 defeat at the hands of Borussia Dortmund in their first pre-season fixture in China. They face Pep Guardiola's Manchester City next friendly fixture on 25 July in Beijing.