Former United midfielder Scholes, now a television analyst with BT Sport, didn’t spare his old side.
“The quality on the ball was as poor as you’ve seen from a Man United team, and that’s just the way it is at the minute,” Scholes said. “You’re not sure what you’re going to get.
“Rashford is probably the only shining light really and he didn’t have his best game today, but he looked a threat. I just think in possession Man United were really, really poor.
“Individually it wasn’t good enough. In possession it wasn’t good enough. So sloppy, giving the ball away all the time.”
Scholes, who retired from football for a second time in 2013, spent his entire career at United, mostly in central midfield.
But it is in this area of the field that Scholes believes United have their greatest problems, saying his former team-mate Michael Carrick, an unused substitute against Watford, ought to start.
Scholes was concerned by how often Watford opened up United’s defence, adding: “I expected them to be a lot tighter defensively, especially with bringing Chris Smalling in, but they were all over the place and every time a ball came into the box you felt Watford were going to score.
“Something’s not right there. The cohesion of the team isn’t there. He (Mourinho) needs to find the right mix of players.”