The invention relates to a disposable tap (1) for tapping liquid from a pressurized liquid container. Compared to prior art taps, the inventive disposable tap is modified so that it can be preferably placed in the upper area of the lateral wall of the liquid container. To this end, the tap comprises a lateral inlet opening (21) which is oriented downward when the tap is mounted and which is provided for coupling, in a sealing manner, to an ascending tube (34), and comprises elements (6, 7, 8), which control the entrance of liquid into the tap and to the outlet (of the tap hole) in an appropriate manner. The invention also relates to a liquid container with a corresponding opening (36) for and with this tap.