An orthogonal components relay channel subject to structured interference is studied. Modeling interference as a structured signal is accurate for scenarios in which the interferer is another source communicating with its own destination. It is assumed that interference is known non-causally at the source and the relay is used for both forwarding the source message and for cooperative interference mitigation. Several transmission strategies based on partial decode-and-forward relaying and leveraging the interference structure are proposed. Achievable rates are derived for discrete memoryless models and Gaussian channels. Finally, numerical results suggest several advantages of utilizing the interference structure at the source, relay or destination in the scenarios at hand.