This is the 3387th most frequent Korean word.
달성한
"달성한" means "achieved."
The word '달성한' is used as a descriptive adjective describing the noun '사람' (person), indicating one who has achieved.
그는 어려운 목표를 달성한 사람입니다.
He is a person who has achieved a difficult goal.
Here, '달성한' forms a defining relative clause modifying the '승리'(win), highlighting the act of achieving specified by the team.
이 팀이 이번 경기에서 승리를 달성한 것은 놀라운 일이었다.
It was remarkable that this team achieved a win in this match.
In this sentence, '달성한' qualifies '성과' (achievement), attributing their accomplishment to the subject.