Celeste Mucci and Camryn Newton-Smith started the final day of the heptathlon in the long jump and javelin.

Mucci, who started the day in fourth, jumped to 6.13m and remained within sight of the podium before finding a personal best in the javelin, her weakest event, with a throw of 43.03m to put her into third.

Teammate Newton-Smith looked to improve from day two and started well with 5.66m jump then a personal best of 44.87m in the javelin as she moved up the table.

It came down to the final event, whether Mucci would hold onto a bronze medal but she needed to hold off Adriana Rodriguez and Adrianna Sulek.

Mucci tried to close the gap created and hold on to the bronze, but Rodriguez and Sulek were too strong as Mucci had to settle for fifth, which is the best finish by an Australian at the World U20s. 

Newton-Smith finished her heptathlon with a new personal best in the 800m of 2:23.11 and brought her total to a lifetime best score of 5487 to place equal 14th. 

Mia Gross and Riley Day were back on the track for the 200m heats with both automatically progressing to the semi-finals.

The last time Australia had a finalist in this event was back in 2000 and unfortunately it looked like that would continue.

Day had to pull out of the semi-finals due to hamstring trouble but Gross, although she didn't qualify for the final, said she had the best run of her life.

“That was amazing. I came off the bend and it was the best bend I have ever run in my life,” Gross told Athletics Australia.

“I am super stoked. I haven’t run that quick in a long time. If conditions were alright I reckon that would have been a PB,” she said.

Gross finished 12th overall with a time of 23.86.