Chris Smalling has admitted that the striking pair of Odion Ighalo and Troy Deeney will cause problems when Manchester United host Watford in Wednesday's English Premier League clash at Old Trafford.
In the reverse fixture at Vicarage Road, United won 2-1 with Deeney converting from the spot after Ighalo was fouled in the 18-yard box.
Smalling, who missed United's 3-2 win against Arsenal on Sunday, described Ighalo and Deeney as tough to handle.
"They were a real handful last time," Smalling told the Daily Star. "Not a lot of teams play with two up front and they're two guys who can run in behind the defence, hold the ball up, play it out and they can obviously both finish as well.
"They were a handful when we played against them and I've seen them play in the same way many times this season."
Smalling went on to praise the Hornets for their performances so far this season.
He added: "Watford deserve full credit for going for it this season, attacking teams and not sitting behind the ball. They deserve to be where they are in the league table."
Watford, who gained promotion to the EPL this season, are currently 12th in the league table.