An anti-torque rotor includes a mast rotatable about a first axis; a plurality of blades; an element slidable along the first axis, rotating integrally with the mast and operatively connected to the blades. The rotor also has a slidable control rod; a first bearing with a rotatable first ring, a second ring radially internal to the first ring and a plurality of first rolling bodies; a third ring slidable along the first axis and angularly fixed with respect to the first axis; and a locking element arranged in a first configuration, in which it prevents the relative rotation of the second and third rings and is movable from the first configuration to at least one emergency configuration, in which it renders the second ring free to rotate with respect to the third ring, when the first bearing is in a failure condition.