A gas burner having a combustion chamber with a bottom and a circumferential wall. A plurality of fuel exit ports are disposed in the circumferential wall, and are directed generally inwardly toward the combustion chamber and upwardly from the bottom of the combustion chamber. The fuel exit ports are preferably directed inwardly at an angle that is slightly rotated from a central axis of the burner to create a swirling flame. A plurality of secondary air inlets extend through the bottom of the combustion chamber. An injector orifice is aligned with the central axis of the burner. The injector orifice is secured to the cooktop using a bracket, which has an orifice-securing surface, with two sidewalls extending therefrom and terminating in fastening flanges. The fastening flanges have asymmetrically arranged slots therein to receive tabs extending from the burner to ensure proper alignment of the burner and the injector orifice.