  We introduce a method for summing Feynman's perturbation series based on
diagrammatic Monte Carlo that significantly improves its convergence
properties. This allows us to investigate in a controllable manner the
pseudogap regime of the Hubbard model and to study the nodal/antinodal
dichotomy at low doping and intermediate coupling. Marked differences from the
weak coupling scenario are manifest, such as a higher degree of incoherence at
the antinodes than at the `hot spots'. Our results show that the pseudogap and
reduction of quasiparticle coherence at the antinode is due to
antiferromagnetic spin correlations centered around the commensurate
$(\pi,\pi)$ wavevector. In contrast, the dominant source of scattering at the
node is associated with incommensurate momentum transfer. Umklapp scattering is
found to play a key role in the nodal/antinodal dichotomy.
