Javi Gracia bemoaned Watford's unfortunate recent run of refereeing decisions following the contentious non-awarding of a penalty in the 3-0 loss to Liverpool.
Official Jon Moss deemed Andy Robertson's rash challenge on Will Hughes not to be worthy of a spot-kick early in the second half at Vicarage Road.
Scores were level at the time of the incident, but Liverpool soon broke the deadlock through Mohamed Salah before Trent Alexander-Arnold and Roberto Firmino sealed the result late on.
Watford were also denied a seemingly clear penalty in their 1-1 draw with Southampton before the international break, but Gracia was hesitant to criticise Premier League officials.
"In the last two games we have been unlucky with some decisions," Gracia said.
"I prefer to always support the referee and I think if I don't say anything about their work in these two games, I will not do so for the rest of the season."
Watford had managed to keep the unbeaten visitors scoreless for over an hour, only to be left with a second defeat in three Premier League matches.
Gracia felt the final scoreline was an unfair reflection of his side's performance.
"I think it was a game closer than the scoreline but, playing against [Liverpool], they're a very good team and they're able to do this," he said.
"We tried to do our work and do our best, but after the first goal we tried to score and with more spaces they are very dangerous."
