GLASGOW • At just 18, Simone Biles has already written her name into the gymnastics history books.

The 1.45m American with the dazzling smile stole the show at the World Gymnastics Championships in Glasgow on Thursday night with an incredible acrobatic display, sealing an unprecedented third consecutive world all-around title.

Some nerves were evident as she fought to stay on the beam and stepped off the mat during her floor routine. But it was enough for a combined total of 60.399 points to seal her eighth world gold to a standing ovation at the Hydro Arena.

She scored highest on the vault (15.833) and the floor (15.266) to lead an American 1-2 - ahead of Olympic all-around and team champion Gabby Douglas by 1.083. Romania's Larisa Iordache claimed bronze.

"Everyone wanted the 'three- peat' and I wanted it too, so tonight I felt the pressure and it wasn't my best meet," said Biles.

"What surprises me is that it was a bad meet for me and to still come out on top with the largest margin of victory (of my three titles) was really crazy because I could have done so much better."

She becomes the first woman since Russian Svetlana Khorkina to win three all-around titles and the first to bag three in a row, after winning in Antwerp in 2013 and in Nanning last year.

Khorkina, who won her first all-around title at age 18 in 1997, also triumphed in 2001 and 2003.

It has been an incredible journey for Biles, since she burst into the limelight in 2013 as Douglas took a two-year break after her Olympic success.

Since then, she has become the holder of 11 world medals and even has a gymnastic move named after her - the "Biles" double layout with half turn on the floor.

Now the most bemedalled US gymnast (11), overtaking Alicia Sacramone, Biles has a chance to reap more here in the finals of the vault, floor and beam.

"Hopefully, I can (win more gold). I still have three (apparatus) finals to go and we'll see what happens," said the Ohio native.

Biles moved to Texas at the age of three to be brought up along with her younger sister Adria by her maternal grandparents.

The couple adopted the children after their mother was struggling with drug addiction.

Biles calls her grandparents Mom and Dad. Both were cheering in the stands in Glasgow as she also helped the US retain the team title.

Aged six years, Biles first got a taste of gymnastics when she went to a training facility for children in Houston, where her flexibility and natural ability to flip caught the coach's attention.

She was homeschooled during her high-school years to focus on her sport.

She has a gruelling training schedule of six days out of seven.

She now dreams of one thing - competing in the Rio Olympics - where, if she takes gold, legend status awaits her.

Since the event was introduced to the Olympic programme in 1952, only three women have claimed back-to-back world and Olympic titles: Larisa Latynina, Ludmilla Tourischeva and Lilia Podkopayeva.

Champion gymnasts of the calibre of Khorkina and Shannon Miller have fallen victim to the "curse of the world all-around champion".

However, Biles is determined that she will not be adding her name to the list.

"That's a stat that's been placed into everybody's head that you can peak too soon," she said.

"We have a peaking pace and I think my pace is just fine.

"I don't think I have peaked yet."

AGENCE FRANCE-PRESSE, REUTERS