play into someone's hands
US /pleɪ ˈɪntu ˈsʌmwʌnz hændz/
UK /pleɪ ˈɪntu ˈsʌmwʌnz hændz/

1.
正中下懷, 中計
to do exactly what your opponent wants you to do, so that they gain an advantage over you
:
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By arguing with him, you're just playing into his hands.
和他爭論,你只是正中他下懷。
•
The opposition's mistakes played right into the government's hands.
反對派的錯誤正中政府下懷。