But she missed out on a medal on the beam as, just as in the all-around final, she fell to finish sixth in an event won by Ukraine's Iryna Krasnianska.
Australia were third best as a result of 25-year-old Rizzo's gold and Prashanth Sellathurai's pommel horse silver on Friday.
Rizzo scored 16.125 to push defending champion Aljaz Pegan of Slovenia into silver-medal position with a score of 15.900, with Greece's Vlasios Maras taking bronze.
Earlier Yang won the parallel bars gold ahead of Tomita, who had to settle for joint silver with South Korea's Yoo Won Chul.
Tomita also finished second in the all-around after losing his title to Yang.
Dragulescu, meanwhile, claimed his sixth world gold.
A day after winning his third world floor title, the 26-year-old from Bucharest took his third vault gold with a combined 16.487 after two jumps.
Dimitri Kaspiarovich of Belarus took silver (16.312) with Hambuechen taking bronze (15.825).
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