  Finding unambiguous evidence of non-trivial pairing states is one of the
greatest experimental challenges in the field of unconventional
superconductivity. Such evidence requires phase-sensitive probes susceptible to
the internal structure of the order parameter. We measure the Little-Parks
effect to provide clear evidence of an unconventional superconducting order
parameter in 4Hb-TaS$_2$. Namely, we find a $\pi$-shift in the
transition-temperature oscillations of rings made of a single crystal. We argue
that such an effect can only occur if the underlying order parameter belongs to
a two-dimensional representation, in other words there are two degenerate order
parameters right at the transition. Additionally, we show that $T_c$ is
enhanced as a function of the out-of-plane field when a constant in-plane field
is applied. Such an increase is consistent with a chiral state, which again, in
general only emerges from a two-component order parameter. In combination with
previous experiments, our results strongly indicate that 4Hb-TaS$_2$ indeed
realizes a chiral superconductor.
