Sevilla had hoped to be challenging for Champions League football this season, but they sit 13 points adrift of fourth place with 15 matches left.
Last weekend Barcelona won at the Estadio Ramon Sanchez Pizjuan to extend Sevilla's losing streak to three matches.
The Andalucian side have won just once since the turn of the year, but their coach is adamant that his men are not disheartened.
"We are in a confident mood," Emery told a press conference.
"The team is solid in terms of its mentality and the players are aware that we have to get back to winning ways and I see that they know this. We are close. We can't beat ourselves up about this (run)."
Sevilla were so incensed by some of the officiating in the game against Barcelona that they took it upon themselves to release a montage of the mistakes made by referee Jose Antonio Teixeira during the 4-1 defeat.
Sevilla must move on quickly from the controversial 4-1 loss though, as they know another defeat on Sunday against Valencia would prove costly.
Valencia and Sevilla are level on 31 points - six behind Real Sociedad, who occupy the final Europa League qualification spot.
Emery is determined to bring European football back to Sevilla next year and he therefore understands the importance of Sunday's game against Juan Antonio Pizzi's men.
"It's a very important match for us," he said.
"We are concentrating on trying to break this negative run.
"That's the only thing were are thinking about.
"We are at home, surrounded by all our fans. We have to feel strong at home and ready.
"We know it's important because we need to end this run, against a team that is level on points with us.
"We have been playing well but we have to be more efficient. That's what has been lacking and that is what we need to end in the next few matches."
Last week Valencia beat Sevilla's neighbours Real Betis 5-0 to extend their unbeaten run to four matches.
Chile striker Eduardo Vargas insists Valencia have not given up hope of bridging the 13-point gap that separates the club from fourth place Athletic Bilbao.
"With the strong team what we have, I see Champions League football as a possibility," Vargas said at a press conference.
"We have our focus set on La Liga at the moment, but are also looking to go as far as possible in the Europa League as well," he added.