The gravity part of the Mars Express Radio Science Experiment consists in measuring gravity data near pericenter above selected target areas of geophysical interest. The low altitude of the Mars Express at pericenter (263--329 km) makes it a very sensitive gravity sensor at small wavelengths which can give new constraints on the local structure of the crust and lithosphere. Mars Express gravity data can also be used to check the quality of the existing global gravity solutions. In this paper, we show that Mars Express gravity data confirm in the Tharsis area the validity of existing global gravity solutions. In particular, the resolution of the most recent global gravity solution is excellent up to harmonic degree 73 and the amplitude at short wavelength is not biased toward zero by the power law regularization up to the same degree.