Inverness inflicted Hamilton's fourth Premiership defeat in a row as Martin Canning's first match since becoming player-manager ended in frustration.
The hosts' Michael McGovern made excellent saves from Billy McKay and Josh Meekings but could not prevent Grant Gillespie's unfortunate own goal.
And although Hamilton looked assured, they fell further behind in 76 minutes when Nick Ross swept home.
The goals gave Inverness their fifth consecutive league win.
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