A 1-0 reverse against Real Betis on Sunday, extending Valencia's winless league streak to 12, increased the pressure on Neville.
"The fans don't want to hear words at this moment in time ... even I'm tired of hearing my own words at the moment," he told a news conference on Tuesday.
"I've got full belief in myself, full belief in the players and the only thing we can do to turn this around ... is win football matches."
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The 7-0 defeat by Barcelona in the Cup semi-final first leg last week represented a watershed moment for some Valencia fans who called for Neville to leave and barracked him at the club's training ground.
Neville said that he was working with a "committed" group of players and recent results had not reflected their displays.
"The chances we had to win these games are quite incredible. When those moments change for us in matches then the confidence will return in full because we now have all our players fit.
Valencia host Barca in the Cup second leg on Wednesday and while Neville said their task was "near-on impossible", he wanted his side to show a "positive mentality".
Neville is likely to make changes as he prioritises Saturday's home league game with lowly Espanyol.
"I want a performance to show the fans we are desperate to turn this around."
(Writing by Justin Palmer in London; Editing by Tom Heneghan)
