South Korea, ranked 18th, improved to a perfect 12-0-0 against 32nd-ranked Vietnam.
South Korea thought they opened the scoring in the third minute, though forward Son Hwa-yeon had her goal wiped out on a borderline offside call.
Ji made it moot about a minute later, as she converted Choe Yu-ri’s pass for her 60th international goal in her 132nd match.
In the seventh minute, Choe was involved in another scoring play, as she crossed for Lee Geum-min for a header that went in off Tran Thi Phuong Thao.
The South Koreans appeared to take their foot off the gas a bit after taking the two-goal lead, and couldn’t extend that lead in the first half despite a massive edge in shots and ball possession.
South Korea found the woodwork twice in the second half. First, it was Jang Selgi hitting the top of the crossbar in the 63rd minute with a right-footed shot from outside the box.
A dozen minutes later, Son Hwa-yeon redirected Ji’s corner with a header, only to have it bounce off the right post.
Ji finally put South Korea up 3-0 in the 81st minute by converting a penalty, awarded after Jang’s shot attempt from the left side of the box went off the left hand of the sliding defender Chuong Thi Kieu.
South Korea will next play 46th-ranked Myanmar on Monday while Japan, who are ranked No. 13 and two-time defending champions, will be South Korea’s final opponent in the group stage next Thursday.
All South Korean matches will be played at Shree Shiv Chhatrapati Sports Complex.
Japan blanked Myanmar 5-0 earlier Friday.
South Korea have never lost to Myanmar in their six previous meetings, and their first real test likely won’t come until they play Japan.
There are three groups of four teams. The top two teams from each group, plus the two-best third-place teams, will advance to the quarterfinals scheduled for Jan. 30.
South Korea are trying to win the Women’s Asian Cup for the first time. Their best performance to date was a third-place showing in 2003.
On Friday, four South Korean players — defender Kim Hye-ri, goalkeeper Yoon Younggeul, midfielder Park Ye-eun and midfielder Cho Mi-jin — were held out of the lineup after testing positive for COVID-19.
Source: Yonhap News Agency