Who opened if anyone for Led Zepplin May 11 1973 in St. Louis or for their 1973 North American tour?

During their 1973 North American tour, Led Zeppelin was supported by the band The Who for several shows, including their concert on May 11, 1973, in St. Louis. This tour also featured other opening acts, but The Who is the most notable. The collaboration between these two iconic rock bands generated significant excitement among fans during that era.