This invention relates to a thread guide unit (6) for drawing off a thread (4) from a rotor (2) of a spinning unit (1) of an open-end spinning machine with a draw-off tube (18) and a compressed air nozzle (21). In accordance with the invention, it is proposed that thread outlet element (19) is provided, a thread outlet element (19) is provided and a mouth (23) of the compressed air nozzle (21) is formed as a gap between the draw-off tube (18) and the thread outlet element (19). The invention also relates to an open-end spinning machine with a multiple number of spinning units (1), whereas each spinning unit (1) features a spinning assembly (3), a thread guide unit (6) in accordance with the preceding description, draw-off rollers (5), a spooling unit (9, 11) and a thread setting unit (15, 14, 16). The invention further relates to a method for operating a spinning unit (1) of an open-end spinning machine, whereas, if the thread (4) must be set, a thread setting unit (15, 14, 16) moves a thread end (17) to the thread guide unit (6), where the thread end (17) is initially fed into the thread guide unit (6) by a negative pressure prevailing in the spinning assembly (3) and is then sucked into the spinning assembly (3), whereas a compressed air flow, which emerges in particular from a compressed air nozzle (21) of the thread guide unit (6) supports the sucking in of the thread end (17) into the spinning assembly (3), in a manner synchronized with the setting of the thread (4).