  Fulfilling the goals of space-based exoplanetary transit surveys, like Kepler
and TESS, is impossible without ground-based spectroscopic follow-up. In
particular, the first-step vetting of candidates could easily necessitate
several hundreds of hours of telescope time -- an area where 2-m class
telescopes can play a crucial role. Here, we describe the results from the
science verification of the Ond\v{r}ejov Echelle Spectrograph (OES) installed
on the 2-m Perek telescope. We discuss the performance of the instrument as
well as its suitability for the study of exoplanetary candidates from
space-based transit surveys. In spite of being located at an average European
observing site, and originally being conceived for the study of variable stars,
OES can prove to be an important instrument for the exoplanetary community in
the TESS and PLATO era -- reaching accuracies of a few tens of m/s with
reasonable sampling and signal-to-noise for sources down to V$\sim$13. The
stability of OES is demonstrated via long-term monitoring of the standard star
HD~109358, while its validity for exoplanetary candidate verification is shown
using three K2 candidates EPIC~210925707, EPIC~206135267 and EPIC~211993818, to
reveal that they are false positive detections.
