Muskett (54) covered 205.14km in the 24hr race in Seoul, to finish as the 11th woman.
She was the first Commonwealth woman home.
She had finished 11th last year but covered only 200.478km.
The race took place in 26degC heat, and Muskett covered about 110km in the first half of the race.
She said she was aiming for 205km so to get there was great.
Her body had recovered well from the race, though she has blisters on the left side of her feet as every turn on the 923m course was to the left.
There were 162 runners in the event, with the winner in the women's category covering 238km, while the fastest man covered 272km.
The biggest obstacle in the event was when lights went out at night for about an hour, but the competitors managed to get around the course.
She was now aiming to compete in the first Commonwealth 24hr race at Keswick in northern England in September next year.
Her training would resume about Christmas and she hoped to compete in the New Zealand 100km championships at Taupo in February in a warm-up for her trip to the United Kingdom.
