The Mestalla outfit struggled in the early part of the season, but have now gone five matches unbeaten to move into seventh position in the table.
"We've won five games in a row. And that's very important after the bad start we had," he told the club's official television channel.
"We're coming together as a team and we want to finish as high in the league as possible. We want to aim for the top four this year. We've improved, and a lot of that is down to the coach."
Guaita, who was strongly linked with Arsenal in the summer, is currently enjoying a run in the Valencia team with first-choice keeper Diego Alves on the sidelines.