Moesha Johnson has won her second gold medal at the World Aquatics Championships, sprinting to the gong in the 5-kilometre race in Singapore.
Just 36 hours after winning gold in a gruelling 10km swim in soupy conditions in Singapore, Johnson backed up by leading from the front in the 5km event.
The Australian beat Italian Ginevra Taddeucci, whom she also beat to gold in the 10km race earlier in the week, in a thrilling sprint finish after 1 hour, 2 minutes and 1 second of swimming.
"A little bit of shock," an exhausted Johnson said after the race.
"That was harder than I expected. The body's not feeling too crash hot.
"To come away with two world titles in two plus days, in 30 degrees plus water, you can't ask for much more than that."
Ichika Kajimoto of Japan finished third, 27.6 seconds behind Johnson.
Dolphins debutant Tayla Martin finished in 20th spot with a time of 1:04.37.
Johnson, the Olympic 10km silver medallist, burst free from the pack just before the start of the third and final lap alongside Taddeucci of Italy, the Paris bronze medallist.
The 27-year-old from northern New South Wales set the pace from early on before delivering a blistering burst of speed just before the final feed zone.
That gap opened up to 15 seconds to the chasing pack with half a lap to go.
Taddeucci stuck with Johnson, who furiously tried to break the elastic to the Italian by varying her line and pace, risking the pair's position at the front of the race.
The cat-and-mouse battle — taking place with a backdrop of shipping containers outside Singapore's bustling harbour — made for a thrilling conclusion to the race.
"I've mad a lot of decisions that have forced me to commit," Johnson, who has moved from Griffith to Miami swimming club since winning her Olympic silver.
"When it comes to a close finish, I just think about what I've been through over the last 12, 18 months.
"Nobody's getting past me."
Water-quality problems had plagued the open water events, leading to several delays at Sentosa, the island area on the coast of Singapore.
The events were delayed due to high levels of E. coli in the water, although that had settled before the 10km events on Thursday.
Water quality is not an unusual problem for open-water swimmers, who also had to deal with multiple delays at the Paris Olympics last year.
Johnson now has three World Championship gold medals to her name.
She will look to defend the mixed relay gold the Australians won in Doha last year, before turning her attention to the pool, where she will compete in both the 1,500m and 800m events.
