The marathoner finished in 2hr 56.10sec to top the podium for the first time in her career. She was followed by Nguyen Thi Dong of Hanoi and Bich Chi from Khanh Hoa province.

"The gold makes my day today although I am not really satisfied with my performance," said Binh. "I expected to break the national record (which stands at 2:48.40) but bad weather and terrain slowed me down."

Binh, who came third in Thailand's Asian Marathon Championship in Pattaya in July, was second in last year's national event in a time of 2hr:54.

Coach Nguyen Tuan Anh, who has trained Binh for about six years, also regretted she failed to break the record.

"Heavy rain and an uneven running track with a lot of cobbles slowed everyone down," Anh said. "Binh tried her best but couldn't reach the target although she won."

He believed Binh would be in the top three in the marathon at the 26th Southeast Asian Games in Indonesia this November.

The competition, which has drawn about 500 athletes to compete in 25 events each for men and women, will conclude on September 15.