LONDON — When the 2017 French Open champion travels internationally, she carries a passport that says Jelena Ostapenko. The same name is listed on the Women’s Tennis Association rankings. “J. Ostapenko” was engraved on the Coupe Suzanne Lenglen after her victory at Roland Garros last month.

But during her quarterfinal match in Paris, one Latvian fan tried to start chants of “Al-Yo-Na,” which were met with perplexed silence by the crowd.

Ostapenko, 20, made a name for herself by winning the French Open title — it just happened to be a name different from what those close to her use.

“I call her Alona,” Latvian player Ernests Gulbis said. “As far as I know, everybody in Latvia, they call her Alona.”

The double identity can cause confusion at home and abroad.

“Almost no one knows that I’m Alona — in Latvia, almost everyone knows it — but here, in WTA, they don’t know it,” said Ostapenko, who is in the fourth round at Wimbledon for the first time and will play Elina Svitolina on Monday.

Ostapenko prefers Alona instead of her legal name, Jelena.

“Everyone who knows, they call me Alona,” Ostapenko said. “I don’t like when people call me Jelena if they know.”

Devoted fans have known to call her Alona for years. In Latvian, it is written with a cedilla under the l, but is sometimes rendered Aliona, Aljona or Alyona. At Ostapenko’s first Grand Slam match at Wimbledon in 2015, a fan arrived with a “Go Alyona” sign.

Anabel Medina, who began coaching Ostapenko this year, had to adjust to calling her Alona.

“I had a couple of times that by mistake I called her Jelena, and she’d turn around and say, ‘Don’t call me Jelena!’” Medina said, laughing.

Ostapenko and her mother, Jelena Jakovleva, say that the family’s desired name of Alona, an ethnically Ukrainian name, was not legally an option to be written on documents because it did not appear in the calendar of Latvian names.

“Because when parents named me Alona, they couldn’t write it down in passport as Alona,” Ostapenko said. “There was no such name in Latvian calendar. I needed to have a Latvian name, something that is on the list. So they couldn’t put me down as Alona, so they put me down as Jelena, because it’s kind of a similar name.”

Though many countries have baby-naming laws that restrict names for a child, experts on Latvian culture could not account for Ostapenko’s rationale. The Latvian calendar to which Ostapenko referred is used to celebrate name days. Each day of the year has associated names, and people with those names are honored as on their birthdays. The calendar is not, however, meant to restrict the validity of names.

“There are no legal restrictions that are or have been in place to prevent using the name Alona on legal documents,” said Karlis Bitenieks of the Terminology and Legal Translation Department at the Latvian State Language Center.

Paula Pralina of the Latvian Institute also said there would have been no restrictions on Ostapenko’s being named Alona, adding that it was possible that there was a misunderstanding at the state office when her name was registered.

“The name-day calendar is meant only to designate in which day you are supposed to celebrate your name day, not as a guide about what names you are allowed to give your child,” Pralina said. “In general, Latvians are naming their babies as they please. Some go for traditional names, some invent completely new ones.”

Adding to the confusion, Jelena is not on the traditional name-day calendar, either. Both Jelena and Alona appear only on the extended version, associated with Aug. 18. After Ostapenko’s triumph in Paris, though, the calendar could change.

“After she’s a Roland Garros winner, our Latvian government wants to put into the Latvian calendar the name Alona,” Jakovleva said, beaming with pride.

Pralina confirmed that the name had been nominated for inclusion in the traditional name-day calendar and said the Latvian State Language Center would decide on the suggestion at its meeting next year.

Ostapenko has been referred to as Alona in Latvian media, dating at least back to articles documenting her prodigious talent at age 14 in 2011.

Rolands Norietis, who was the lone Latvian journalist covering the French Open until a television crew arrived when Ostapenko reached the final, said he called her Alona in his coverage to follow the established precedent, admitting some ambivalence about the practice.

“I do it because others before me started doing that,” Norietis said. “But normally you should stick to the official name, don’t you think?”

Ostapenko, who said she enjoys hearing either name chanted from the stands, said it was too late now to switch her legal name.

“I thought about changing it, but now everyone knows me as Jelena, so it’s a bit difficult,” she said. “People will think that there is another player with a different name.”