A diffuser case support structure for a gas turbine engine includes a fairing disposed circumferentially about a longitudinal axis. The fairing defines a plurality of passages circumferentially spaced apart and forming at least a portion of a fluid path between a compressor and a combustor of the gas turbine engine. A diffuser frame includes a plurality of struts. Each of the plurality of struts is disposed between a pair of adjacent passages of the plurality of passages. The diffuser frame is configured to couple an inner diffuser case to an outer diffuser case. A sliding joint is formed between the fairing and the diffuser frame, the sliding joint comprising a fastener extending generally axially through an aperture disposed in the fairing.