An 84th minute goal from Yan Aung Win helped the host nation scrape a narrow 1-0 victory against Brunei on Friday, and move one step closer to making November's final stages of ASEAN's premier international tournament.
However, despite the winning start to their campaign, Park was quick to acknowledge that defensive frailties could be Myanmar's undoing as the qualification process continues.
"It was a tough match and we needed a late goal to win in so I feel very happy with this result and I am very proud of the Myanmar team," the Korean told the Suzuki Cup's official website.
"But we had some problems (against Brunei) and our weakest point was our defence.
"Brunei played lot of long balls towards our defence which caused us problems because we could not compete in the air with their players.
"There is little that we can do about it now, but in the future we will try to improve our players so that they are better at dealing with that sort of problem," he added.
Myanmar are in action again on Sunday when they face Timor Leste who sensationally beat Cambodia 5-1 in their opener. Laos will play the Cambodians on the same day.