More than 1,400 Hornets made the trip to Lancashire from Hertfordshire to see their side beaten by the Clarets at Turf Moor, prompting the following from the Brazilian.
"We didn't show up," Gomes said.
"Of course Burnley deserve credit, but we didn't play the way we have in the last few games.
"Apologies to the fans who came all the way from Watford to support us tonight.
"We couldn't control the ball or pass the ball.
"We invited them to press us and we knew they were going to press us because Liverpool conceded in this way against them."
Gomes added further: "We play again in a few days and we need to show up.
"We know our qualities and we must get back to showing them on Saturday."