The Hornets suffered a 1-0 defeat away from home in the second game of the Premier League season.
But Deulofeu believes that his side's performance merited a draw.
"We got some chances and they didn't deserve this win," said Deulofeu to reporters after the game.
"Maybe a draw will be the best result.
"In some periods of the game, yes, we played well but also in some periods of the first half, we didn't play well.
"We have to go more strong to the challenges and if you didn't take the three points, the game is bad. If you lose, it's bad, so we have to go again.
"We will have to improve some things and start to take points because now other teams have started to take points and we have to also take them."