But it could never have come to pass without the vision, ambition and faith of the Spanish club's extraordinary president Fernando Roig. When Roig bought control of the club in 1998, Villarreal had less than a handful of employees and played in front of a maximum of 3,000 home fans, nicknamed 'Yellow Submarine' as they floated between the divisions.
Training was conducted wherever there was an available flat piece of ground and the view from the lower reaches of Spain's second flight up to the highest echelons of European football seemed to require not so much a man of vision as someone with a powerful telescope.
Since then the club have become a muscular presence in Spain's Primera División, as well as winning two UEFA Intertoto Cups and sprinting from a European bow in 2002 to their 50th UEFA competition match. After winning Group D this season, Villarreal will be confident of progressing even further after being paired with Scottish side Rangers FC in the last 16.
Twice holding United at bay and winning against SL Benfica and LOSC Lille Métropole, this has been a notable UEFA Champions League debut, but Roig has higher hopes: "My big aim isn't simply for Villarreal to play in the UEFA Champions League but for us to win it one day.
"I'm not going to put a limit on our ambition in this competition," Roig told uefa.com. "The great news is that the UEFA Champions League anthem will be playing at El Madrigal again in the spring and our next game will be on an evening which isn't quite as cold as it was when we played Lille.
"I hope and pray this is our year to reach the final and who knows, it could be," he continued. "This season has seen us make a massive leap forward and now we have passed yet another stage by qualifying first in a group that some people thought we might struggle in - and we have eliminated a great club like Manchester United."
However, the man whose immense football skills are the basis for Villarreal's recent achievements, Riquelme, has words of caution. "We have to be proud that we have qualified and take satisfaction in turning another page in the history of the club by winning the group," he told uefa.com.
"I am aware that in previous years some unexpected teams like [AS] Monaco [FC], [FC] Porto and Bayer  Leverkusen have reached the UEFA Champions League final," added the Argentinian international. "But we also have to be realistic about how we played in defeating Lille. I wouldn't say that we played all that well and we will need to improve. We have qualified for the last 16 and that's all."
©UEFA.com 1998-2017. All rights reserved.