A capsule designed for preparation of a beverage upon injection of liquid under pressure into the capsule, the capsule containing a substance for preparation of the beverage and comprising a cup-shaped body, a top wall and a bottom retaining wall, wherein the capsule further comprises opening means designed to open the retaining wall upon rise in pressure in the capsule, wherein the opening means comprise a plurality of first elements, and secondary elements (14a, 14b, 14c) associated with each first element and facing the retaining wall, the secondary elements (14a, 14b, 14c) associated with a respective first element surrounding at least partially the respective first element and being arranged adjacent to but not in contact with the respective first element, the first elements being non-linear elements, preferably Y-shaped elements, and the secondary elements (14a, 14b, 14c) being linear elements, wherein the secondary elements (14a, 14b, 14c) are arranged at a larger distance to the retaining wall than the first elements are, wherein the retaining wall is a thin film having a thickness of between 15 and 25 microns, wherein the capsule further comprises a series of dispensing holes (16a,16b) having a diameter of at least 0.4 mm, preferably at least 0.5mm, and wherein the substance is a precursor ingredient of roast and finely ground coffee, characterized in that, for each first element, the associated secondary elements (14a,14b,14c) comprise three linear segments that are arranged to at least partially surround the respective first element, wherein two linear segments (14a, 14b) are arranged at a medium distance to the retaining wall, and wherein one linear segment is arranged at a larger distance to the retaining wall than the medium distance and is arranged radially outwards with respect to the respective first element. wherein the capsule further comprises opening means designed to open the retaining wall upon rise in pressure in the capsule, wherein the opening means comprise a plurality of first elements, and secondary elements (14a, 14b, 14c) associated with each first element and facing the retaining wall, the secondary elements (14a, 14b, 14c) associated with a respective first element surrounding at least partially the respective first element and being arranged adjacent to but not in contact with the respective first element, the first elements being non-linear elements, preferably Y-shaped elements, and the secondary elements (14a, 14b, 14c) being linear elements, wherein the secondary elements (14a, 14b, 14c) are arranged at a larger distance to the retaining wall than the first elements are, wherein the retaining wall is a thin film having a thickness of between 15 and 25 microns, wherein the capsule further comprises a series of dispensing holes (16a,16b) having a diameter of at least 0.4 mm, preferably at least 0.5mm, and wherein the substance is a precursor ingredient of roast and finely ground coffee, characterized in that, for each first element, the associated secondary elements (14a,14b,14c) comprise three linear segments that are arranged to at least partially surround the respective first element, wherein two linear segments (14a, 14b) are arranged at a medium distance to the retaining wall, and wherein one linear segment is arranged at a larger distance to the retaining wall than the medium distance and is arranged radially outwards with respect to the respective first element.