Japan's Nao Kodaira missed her chance to defend her overall title at the World Sprint Speed Skating Championships on Sunday after she pulled out of her final race due to feeling unwell.

Pyeongchang Olympic Games 500-meter gold medalist Kodaira, who held onto the lead after winning the day's 500-meter race, withdrew from the 1,000 meters. She thereby failed in her bid to become the first Japanese to repeat as overall champion, while Netherland's Jorien ter Mors claimed the title.

"I'm frustrated that I couldn't pull myself together even though I did everything I could to condition myself to defend my title," Kodaira commented through her coach Masahiro Yuki. "I was more tired than I thought I was, so I just want to do my best to recover and focus on my next race."

Earlier in the day, Kodaira extended her unbeaten run in the 500 meters to 27 races. She crossed the line in 37.72 seconds, 0.14 ahead of ter Mors, who won gold in the 1,000 meters at Pyeongchang.

At the meet, competitors race four times, twice each over 500 and 1,000 meters, to determine the overall winner. Kodaira won the title last year in Calgary, Canada.

The 31-year-old, who also won silver in the 1,000 at Pyeongchang, said she had a cold on Saturday, when she won her 500 meter-race and finished fourth in the 1,000 at the meet.

She is slated to compete at the two-day World Cup meet in Minsk, Belarus, beginning on March 17, but Yuki said he wants to consider her schedule carefully.