There was a bit of confusion when Jose Mourinho was spotted in the crowd for Belgium's 2-0 win over Iceland in the UEFA Nations League.

Manchester United men Marouane Fellaini and Romelu Lukaku were both absent from Roberto Martinez's squad.

So naturally, it was assumed Mourinho was on a scouting mission to get a closer look at long-term transfer target Toby Alderweireld.

The United manager is a keen admirer of the Tottenham centre-back and was desperate to secure a deal for him in the summer.

Mourinho was keeping an eye on the Spurs defender during the Iceland game, but he had another reason to make the trip to Brussels.

According to Belgian football expert Kristof Terreur, Mourinho was also keeping an eye on Borussia Dortmund's midfield maestro Axel Witsel, per HLN.

Witsel was one of the star men in Belgium's run to the World Cup semi-final, earning him a move back to Europe after a one-year stint in China with Tianjin Quanjin.

He's been in stellar form since arriving at Dortmund, with Lucien Favre's side currently top of the Bundesliga.

Given Nemanja Matic and Fred's struggles this season, targeting a midfielder would be a pretty sensible thing for Mourinho to do.

Witsel's mobility, passing range and skill on the ball would make him a far better option going forward than Matic at the base of United's midfield.

However, getting Dortmund to sell would be a very tough task - and would likely cost a small fortune.

Given United's lacklustre start to the season, Mourinho and the Red Devils board are going to have to make a big statement in January.

There have been rumours linking the club with Inter Milan duo Ivan Perisic and Milan Skriniar, both of whom would greatly improve the current squad.

Calciomercato are even reporting that Perisic could be available for just £31m.