Watford are leaving no stone unturned as they prioritise a new defensive midfielder before the end of the transfer window, and are making former Manchester United target Leander Dendoncker their primary target.

Anderlecht midfielder Dendoncker is one of the club's star players and only team-mate Adrian Trebel made more interceptions of any player in the Champions League group stages this season.

Now aged 22, he made his breakthrough with the Belgian side when he was a 19-year-old and made his international debut a year later.

Anderlecht are believed to be holding out for £22 million for their star youngster, although this may not deter the Hornets as his re-sale value would be considerably higher given his age.

Should they fail on that front, Marseille midfielder Zambo Anguissa is another target.

The Cameroon international has played a part in every game for third-placed Marseille this season, and joined them from Stade Reims in 2015 as a youngster.

Team-mate Luis Gustavo recently singled out the 22-year-old for praise because of his impressive performances for the south coast club.

"There's nothing more interesting or exciting than to see a player increase his level during a season, someone who improves with time," said Gustavo.

"When I arrived, there were three players in the same role as him: Max [Lopez], [Morgan] Sanson and myself. Frank was the fourth option. Time went by and he's become almost indispensable.

"He's playing very well, he's very young, and has a lot of talent. He has really developed his play. I'm also very happy to play with Max and Sanson. Our relationship is just as good: in fact, it's only getting better."

The Hornets also have a third iron in the fire, in the shape of a loan deal for Sunderland midfielder Didier Ndong. Negotiations with the Black Cats began early this week, having previously quietened since the opening week of the transfer window.