By Pritha Sarkar

RIO DE JANEIRO (Reuters) - When Nadia Comaneci takes her seat at the Rio Olympic Arena on Sunday, she will be able to sit back and follow the women's gymnastics competition untroubled by the pent-up tension she usually feels.

That went flipping and somersaulting out of the window long before she headed for Rio to celebrate the 40th anniversary of her 'perfect 10' as, for the first time since 1968, her native Romania failed to make the cut for the team final.

"There will be a big hole in my stomach (on Sunday) when I won’t see my team," Comaneci told Reuters in an interview.

"It’s like someone important is missing from a party because you can’t imagine an Olympic gymnastics competition without Romania."

That is certainly true for a country used to showcasing perfection in the sport ever since Comaneci landed the first 10.0 score during the 1976 Montreal Olympics.

Romania has scooped a team medal at every Olympics since 1976, including gold in 1984, 2000 and 2004, but that remarkable four-decade streak in women's gymnastics ended in bitter tears as they followed up a doomed outing at last year's world championships by also flopping at the Rio test event in April.

"When one member of the team got injured, it started a chain of bad luck as the others were left really shaken and then they just panicked," the 54-year-old Comaneci said.

"...One girl got injured, then one girl fell off bars and then you couldn't stop the mistakes."

Pre-competition injuries to Catalina Ponor and Anamaria Ocolisan had already provided major setbacks but when five-times European gold medalist Larisa Iordache botched her display on the beam at the Glasgow world championships last October, it completed a woeful exhibition of errors for the Romanians.

So poor was their display, no Romanian made it into the apparatus finals -- a competition that even featured an unlikely finalist from India on the vault.

"It was like they were all having a bad day and I started thinking 'can things get any worse?' And it did as they failed to qualify for the Olympics," lamented the five-times Olympic gold medalist.

After finishing 13th at the world championships -- where a top-eight finish was needed for automatic Olympic qualification -- the Rio test event in April offered Romania a second chance.

However, a rapidly shrinking talent pool meant that when they were hit by another round of injuries, a lack of top caliber substitutes meant they again failed to make the Olympic cut.

"In the qualifying event in Rio...they simply didn't have the girls as the only experienced member was Ponor but she can’t do three routines on every apparatus," said Comaneci.

"A lot of people think this is the death of Romanian gymnastics but I don’t think that's true. It’s just an unfortunate situation for now."

Romania's rich legacy is partly to blame for the current crisis as the country's gymnastics boom in the 1970s and 80s meant that countries with deep pockets lured away many of the nation's top-rated coaches.

Comaneci's own mentors, Bela and Martha Karoyli, have replicated that success with the current U.S. women's team, unbeaten in every global meet since 2011, winning three successive world titles and the 2012 Olympic gold.

Martha Karoyli, who will be retiring as USA Gymnastics national women’s team coordinator following the Rio Games, thinks the root cause of the decline in Romania is clear.

"I feel this happened because the system is broken," she said.

"We developed a system in Romania that was very successfully continued for a number of years but I don't know if it was because of some conflict in the organization or whether there was government interference ... but somehow they have forgotten the importance of raising gymnasts to be ready for every Olympics.

"So they had no strong upcoming gymnast to make the Olympic team."

Comaneci hopes her country's no-show when teams from the United States, Russia, Britain, China, Italy, Japan, Canada, Netherlands, Brazil, Germany, Belgium, France line up on Sunday can act as a wake-up call.

"After the (1989) revolution, we had a little bit of difficulty too but we came back from that setback.

"The recovery will be slow but I have not lost my faith in Romanian gymnastics."

In the absence of a fielding a full team, 2004 Olympic gold medalist Ponor will carry Romania's hopes as she looks to qualify for the individual finals.

(Reporting by Pritha Sarkar, editing by John Stonestreet)