Paul Pogba's agent says the France international chose to return to Manchester United rather than take the easier route at Real Madrid because of the challenge on offer at Old Trafford.

Pogba left United in 2012 after not renewing his contract, joining Juventus and going on to win four consecutive Serie A titles and reach the final of the Champions League with the Turin club.

The midfielder was linked with a host of clubs during the transfer window but chose to return to United, doing so in a world-record transfer worth £89million.

Pogba was the headline arrival in a busy window for United, with striker Zlatan Ibrahimovic and midfielder Henrikh Mkhitaryan also joining the club, despite them missing out on Champions League qualification last season.

Agent Mino Raiola brokered each of those deals and told The Daily Mail: "I think Manchester United showed the world this summer that they were not going to stand still, they want to be the best.

"They sent out a message with the transfers they did that this is the biggest club in the world."

On the Pogba deal, he added: "Yes, Manchester United had no Champions League and weren't champions but they needed us the most.

"United had been talking to us for two years about Pogba.

"They had taken my player Sergio Romero and we had kept the lines of communication open.

"We knew we had interest, we spoke to Juventus, they really wanted to try for the Champions League, they gave him the number 10 shirt and we said we would give it one more year.

"Then I worked on an exit plan. We had two offers from the Premier League and two outside.

"Paul said United was in his heart, Woodward wanted him at United a year ago and Mourinho had wanted him at Chelsea too, so when the two combined we knew it was right.

"For the player, Real Madrid would have been easier, La Liga, Champions League, but he wanted the greater challenge."