It all started with a sign. There was nothing fancy about it — just a board with the word “volleyball,’’ and an arrow — but the location couldn’t be beat.

Terry Pettit, the volleyball coach at Nebraska from 1977-99, set it up years ago between the Cornhuskers’ football stadium and the Coliseum where his team played.

“Coach Pettit decided to have volleyball matches after the football games,’’ said John Cook, the Cornhuskers’ current coach. “The Coliseum was right next to the football stadium, so everybody would go out to the east, and they would have to walk by that Coliseum.’’

Pettit hoped a few stray football fans might stop by to check out his team. That invitation grew into a full-blown love affair between a state and a sport, one that brought thousands of rowdy, red-clad supporters to Target Center to cheer their Huskers to a hard-fought, five-set victory over Illinois in Thursday’s NCAA semifinals.

The Huskers, the defending national champions, dropped the first two sets before roaring back to win 22-25, 16-25, 25-23, 25-20, 15-11. They will play top-seeded Stanford, which swept BYU 25-15, 25-15, 25-18 in Thursday’s first semifinal, in the championship match Saturday.

Seeking its sixth NCAA title and its third in the past four years, Nebraska rules the volleyball world in other ways as well. It has led the nation in attendance for six consecutive seasons, averaging 8,205 fans per match at the Bob Devaney Sports Center. It has sold out 253 home matches in a row, an NCAA record.

The Cornhuskers’ matches are broadcast on radio, via a 29-station network that covers the state, and many are televised free statewide by Nebraska Educational Television.

“Volleyball is in the DNA,’’ Cook said. “We call it a state treasure. I have senators and Supreme Court justices texting me after matches.’’

He also has folks such as Stan and June Groth making their voices heard. The Groths traveled from Pilger, Neb. — population 365 — to watch the Huskers at Target Center. Stan even dressed for the occasion, wearing a red sport coat fitted with working Christmas lights and a Huskers Santa cap.

“There are no professional sports in Nebraska, so our college teams are the biggest thing we have,’’ Groth said. “The players are like Hollywood movie stars. And the girls at our high school, they all want to be Huskers. They just think the players are goddesses.’’

Cook, who has led Nebraska to four of its five NCAA championships, came to Lincoln in 2000 to lead a program Pettit shepherded to national prominence. The Huskers never have had a losing record in 44 seasons, going 1,336-244-12.

As Pettit’s signs began drawing overflow crowds to the old Coliseum, the program’s booster club raised money to pay for the public TV broadcasts. Cook said “the whole state bought into’’ Nebraska volleyball at that point — watching the team became a fall ritual for girls and their families. The fervor reached a new level when the team moved to the Devaney Center in 2013, a move that doubled attendance.

That fan base has turned Huskers players from around the nation into the state’s beloved daughters. Senior co-captain Kenzie Maloney, from Louisville, said they are recognized in public and are often asked to pose for photos. Her fellow captain, senior Mikaela Foecke, from Iowa, feels especially fortunate with that kind of support.

“They kind of live and die with us,’’ Foecke said of the fans. “That’s something really special. To have so many people come all the time is unbelievable.’’

Those people showed up loud and proud Thursday. They held signs bearing the Huskers’ slogan, “We Over Me,’’ and hollered their “Roof, Roof, Roof’’ cheer for every Nebraska block.

Illinois prevailed in a back-and-forth first set, thoroughly outplayed the Huskers in the second set, but Foecke and Maloney — in their fourth Final Four — steered it back from the brink.

As the Huskers gained steam, their fans grew louder.

“The Nebraska fans always bring it,’’ a grateful Foecke said. “It’s a huge help.’’