An anti-torque rotor (4, 4') for a helicopter, comprising: - a mast, rotatable about a first axis; - a plurality of blades, hinged on said mast, extending along respective second axes transversal to said first axis and rotatable about respective said second axes to alter the respective angles of attack; - a control element, sliding along said first axis with respect to said mast, integrally rotating with said mast, and operatively connected to said blades to cause the rotation of said blades about respective said second axes following a translation of said element along said axis; - a control rod, sliding axially along said first axis with respect to said mast and angularly fixed with respect to said first axis; and - a connection element, interposed between said control rod and said control element, sliding along said first axis with respect to said mast and integrally with said control rod, and configured to enable the relative rotation of said control element with respect to said control rod about said first axis in a correct operating condition; characterized in that it comprises an interface made of an antifriction material interposed between said control rod and said connection element, so as to enable the rotation of said connection element with respect to said control rod about said first axis in the event of failure of said connection element; and - a tubular element radially interposed between said control rod and said connection element, and axially sliding integrally with said control rod and said connection element; said interface comprising at least a first surface of said tubular element, which is arranged in contact with said control rod, so as to enable the rotation of said tubular element jointly with said connection element, with respect to said control rod; said anti-torque rotor (4, 4') further comprising at least a first sensor adapted to detect the rotation of said annular element; said tubular element, in turn, comprising: - a main body radially interposed between said connection element and said control rod; and - an axial end ridge, which radially projects from said main body towards said connection element; said interface further comprising a third surface of said axial end ridge arranged in abutment against a shoulder of said control rod. - a mast, rotatable about a first axis; - a plurality of blades, hinged on said mast, extending along respective second axes transversal to said first axis and rotatable about respective said second axes to alter the respective angles of attack; - a control element, sliding along said first axis with respect to said mast, integrally rotating with said mast, and operatively connected to said blades to cause the rotation of said blades about respective said second axes following a translation of said element along said axis; - a control rod, sliding axially along said first axis with respect to said mast and angularly fixed with respect to said first axis; and - a connection element, interposed between said control rod and said control element, sliding along said first axis with respect to said mast and integrally with said control rod, and configured to enable the relative rotation of said control element with respect to said control rod about said first axis in a correct operating condition; characterized in that it comprises an interface made of an antifriction material interposed between said control rod and said connection element, so as to enable the rotation of said connection element with respect to said control rod about said first axis in the event of failure of said connection element; and - a tubular element radially interposed between said control rod and said connection element, and axially sliding integrally with said control rod and said connection element; - a main body radially interposed between said connection element and said control rod; and - an axial end ridge, which radially projects from said main body towards said connection element;