First Sydney show in INXS's 'Get Out of the House' pub-and-club tour. You Am I certainly supported INXS at one of their Sydney shows, and this is the most likely contender.

Very difficult to find documentation of the support slots at these small - by INXS's standards - venues, especially given that the shows were not widely advertised at the time. Best guess for supports at the Sydney dates are:

Tue 27th April - Sydney University Refectory - You Am I
Wed 28th April - Temptations Nightclub, Mount Druitt - Jenny Morris
Fri 30th April - Jet Club, Dee Why - unknown, though You Am I played at the Lansdowne this night
Sat 1st May - UNSW Roundhouse - Swoop, according to SMH gig guide
Sun 2nd May - Selina's - Juice