The orbital dynamics of a very young asteroid pair (5026) Martes and 2005 WW113 is studied. We detect strong resonant perturbations of the larger member of the pair (5026) Martes by the 3:11 mean motion resonance with the Earth. The unbounded secondary (2005 WW113) has orbited far from the resonance and is not perturbed. We provide a new estimation of the resonance structure and found that, under the planetary perturbations, a single resonance splits into a multiplet. The nominal position of the resonance is 2.37783 AU. However, the center of the corresponding chaotic zone is detected at 2.37754 AU. As a result, we noted a small but not negligible difference between the calculated and observed position of resonance. The multiplet structure of the 3:11 Earth resonance cannot explain this offset (the position of the main term of the multiplet is 2.377698 AU).