Péngyou bāng tā zài nǚshén miànqián zhùgōng, zhōngyú chénggōng le.
His friend helped him out in front of his crush, and it finally worked.
Tips
usage
助攻 has three registers: (1) military — secondary attack; (2) sports — assist (passing to a scorer); (3) colloquial — helping a friend in a romantic pursuit. The third usage is very popular in modern Chinese internet slang.