  Around fifty years ago, LiTi$_2$O$_4$ was reported to be first spinel oxide
to exhibit a superconducting transition with highest T$_c$ $\approx$ 13.7 K.
Recently, MgTi$_2$O$_4$ has been found to be the only other spinel oxide to
reveal a superconducting transition with a T$_c$ $\approx$ 3 K, however, its
superconducting state is realized only in thin film superlattices involving
SrTiO$_3$. We find that a V-doped Mg$_{1-x}$Ti$_2$O$_4$ phase, which gets
stabilized as a thin surface layer on top of stoichiometric and insulating
V-doped MgTi$_2$O$_4$ bulk sample, exhibits high-temperature superconductivity
with T$_c$ $\approx$ 16 K. The superconducting transition is also confirmed
through a concomitant sharp diamagnetic transition immediately below T$_c$. The
spinel phase of the superconducting surface layer is elucidated through
grazing-incidence X-ray diffraction and Micro-Raman spectroscopy. A small shift
of the sharp superconducting transition temperature ($\sim$ 4 K) with
application of a high magnetic field (upto 9 Tesla) suggests a very high
critical field for the system, $\sim$ 25 Tesla. Thus, V-doped
Mg$_{1-x}$Ti$_2$O$_4$ exhibits the highest T$_c$ among spinel superconductors
and also possesses a very high critical field.
