Dlamini-Zuma said "history has already been made" as she will be the first woman to be on the ballot paper for ANC president.
"As we close this campaign now, it's in the hands of delegates and God," she said.
Dlamini-Zuma said she was willing to accept any outcome, adding: "Whatever happens, the ANC must emerge the winner."
The gala dinner was attended by ministers Bathabile Dlamini, Thoko Xasa, Joe Maswanganyi, Maite Nkoana-Mashabane, Faith Muthambi and Mmamoloko Kubayi.
A number of songs and dances were dedicated to Dlamini-Zuma. The former African Union Commission chairman said ANC delegates must reflect the aspirations of South Africans.
She is up against Deputy President Cyril Ramaphosa.