Zaragoza's fall from grace is one of the shock stories of the Primera Liga season, with the club going from a sixth-placed finish last season to relegation a year later.
"Life goes on and we need to lift ourselves," Villanova said.
The six-time Copa del Rey winners still had a chance of escaping the drop on the final day on Sunday, but their 3-2 defeat at Real Mallorca means they will be playing Segunda Division football next season.
"This has been the end of a season in which luck has turned it's back on us, including the last weekend, where we conceded two stupid goals and we have had chances to win the game," he added.
"We need to continue fighting so that in the coming year Zaragoza return to the Primera Liga, above all for the fans."
"The players are shattered in the changing room, many of them are crying inconsolably because it has been a very tough blow for those professionals. But, we are in the Segunda Division and we will have to get used to the idea little by little."