WASHINGTON, Nov. 1 (Xinhua) -- Ameircan star Simone Biles won her fourth world women's all-around title with 57.491 points at the ongoing World Gymnastics Championships on Thursday.

"It was a tough day," Biles said. "I didn't know if I was going to pull it off today, and then I started doubting myself so I tried to track back to training and see how well that went. I tried to just think of that. You should always go back on training because I've had such good training."

With the win, Biles now has four world all-around titles dating back to 2013, and also has a combined 21 Olympic or world medals. The 21-year-old athlete will have four more opportunities to win world titles in Doha, and she'll be the favorite on three of those events.

Japan's Mai Murakami took silver with 55.798 points, while Biles' teammate and defending world all-around champion Morgan Hurd was third with 55.732 points.

Hurd, the surprise winner in last year's world championships in Montreal, struggled on balance beam. Hurd blamed her beam error on "trying to be too perfect" and said it was difficult to compare her first with the second world championships.

"It is kind of hard to say because they are very different circumstances," said Hurd. "Last year it was my first time, so I did not really know what to expect. This year I came in basically as a veteran, and I had a lot more expectations of myself."

Taking place from October 25-November 3, the 48th world championships featured 22 world and Olympic gold medalists from 13 countries and regions.