The Football Association of Wales has warned fans against invading the pitch should the country qualify for Euro 2016 on Sunday, fearing a points deduction or stadium closure could "spoil" a stellar campaign.
Three points from this weekend's clash with Israel in Cardiff would be enough to see Wales reach a major tournament for the first time in 58 years.
However, with Wales having already been fined after a number of fans entered the field of play during their opening-round victory over Andorra, it is feared Uefa could come down hard in the event of another incident of a similar nature.
"Uefa do look upon these things quite poorly and we know there can be penalties if such things happen," FAW chief executive Jonathan Ford told WalesOnline.
"There is a range of disciplinary procedures and ultimately they do have the ability to take points away from teams or order games to be played behind closed doors.
"It goes without saying we do not want that to happen and potentially spoil what could be a great night.
"We want every single person at the stadium and across the country to enjoy the occasion and hopefully celebrate what could be a fantastic day in Welsh football but all should remember to do it in the right spirit.
"It would be a terrible shame if something like that happened and, come the Andorra game [Wales' final home fixture], we couldn't give the team the sold-out celebration the team deserves."