Media playback is not supported on this device
Smith 'read riot act' to Villa players at half-time
Aston Villa boss Dean Smith wants referees to use pitchside VAR monitors after his side's 3-0 defeat at Watford.
Watford scored twice after having Adrian Mariappa sent off but Smith said both goals should not have counted.
Troy Deeney made it 2-0 with a penalty awarded as Villa defender Matt Targett lay injured while Smith claimed Jack Grealish was fouled before Ismaila Sarr's goal.
"The referee could look at the screen but doesn't," Smith told BBC Sport.
- Ten-man Watford thump Villa in relegation battle
Premier League referees' chief Mike Riley has cautioned against their use by on-field officials because of the additional delay it would cause.
That goes against Uefa guidance and Smith, whose side are in the relegation zone, wants the league to change its stance.
"There's a screen the fella [referee] can walk over to, look at the incident and say 'I made a boo boo'," added Smith.
"But we don't do that in the Premier League. We go to Stockley Park [where VAR is based] where they haven't got a feel for the game. They just make a decision looking at one incident."
Aston Villa have failed to keep a clean sheet away from home in the Premier League since January 2016
Targett was down injured when Deeney, who opened the scoring in the first half, was fouled by Douglas Luiz for the penalty before scoring from the spot.
Smith was also unhappy with Etienne Capoue's challenge on Grealish in the build-up to the third goal - Capoue delivering the assist for Sarr to score.
"Matt Targett goes down with a hamstring injury," added Smith, who signed a new four-year contract last month.
"I understand officials can only stop play because of a head injury. Jack Grealish doesn't know Targett has done his hamstring. We lose the ball and Watford play on.
"I still don't think it should be a penalty. It was shoulder to shoulder and Deeney goes down easily. Targett is playing Deeney onside, sitting on the floor.
"For the third goal, Jack Grealish gets fouled in front of us. The fourth official says their player got the ball but he doesn't.
"It goes to Stockley Park - again no feel for the game. The referee could look at the screen but doesn't.
"I'm frustrated with that but more frustrated with the players."
Villa, who have lost five of their last six league games, are at Burnley on New Year's Day before hosting champions Manchester City on 12 January.
Source: bbc.com