We investigate the crossing-symmetry relation between b→cτ−ν¯ decay and bc¯→τ−ν¯ scattering to derive direct correlations of New Physics in semi-tauonic B-meson decays and the mono-tau signature at the LHC (pp→τhX + MET). Using an exhaustive set of effective operators and heavy mediators we find that the current ATLAS and CMS data constrain scenarios addressing anomalies in B-decays. Pure tensor solutions, completed by leptoquark, and right-handed solutions, completed by W′R or leptoquark, are challenged by our analysis. Furthermore, the sensitivity that will be achieved in the high-luminosity phase of the LHC will probe all the possible scenarios that explain the anomalies. Finally, we note that the LHC is also competitive in the b→u transitions and bounds in some cases are currently better than those from B decays.