The American earned the most individual points after five weeks of competition, finishing on 2408.

She pitched six complete games and her overall win-loss record was 13-1.

Compatriot Jessica Warren, Erika Piancastelli of Italy and Canada's Victoria Hayward completed the top four. 

American outfielder Haylie McCleney was named defensive player of the year. 

The 37-year-old Osterman earned an Olympic softball gold medal at Athens 2004, going on to claim silver at Beijing 2008. 

She is set to compete at next year's Olympic Games in Tokyo, rescheduled from this year due to the coronavirus pandemic. 

The Athletes Unlimited competition format centred on an individual player’s performance rather than teams. 

During games, players got points for "winning" each inning and for each of their individual statistics.

The league featured 57 of the world’s best softball players, including national team members from Canada, Britain, Italy, Mexico, Puerto Rico and the US. 

Games were aired on the Olympic Channel to more than 180 territories outside of the US, Canada and Spanish-speaking Latin America.