  Swift J1842.5$-$1124 is a transient Galactic black hole X-ray binary
candidate, which underwent a new outburst in May 2020. We performed multi-epoch
MeerKAT radio observations under the ThunderKAT Large Survey Programme,
coordinated with quasi-simultaneous Swift/XRT X-ray observations during the
outburst, which lasted nearly a month. We were able to make the first-ever
radio detection of this black hole binary with the highest flux density of
229$\pm$31 $\mu$Jy when the source was in the hard state, after non-detection
in the radio band in the soft state which occurred immediately after its
emergence during the new X-ray outburst. Therefore, its radio and X-ray
properties are consistent with the disk-jet coupling picture established in
other black hole X-ray binaries. We place the source's quasi-simultaneous X-ray
and radio measurements on the radio/X-ray luminosity correlation plane; two
quasi-simultaneous radio/X-ray measurements separated by 11 days were obtained,
which span $\sim$ 2 dex in the X-ray luminosity. If the source follows the
black hole track in the radio/X-ray correlation plane during the outburst, it
would lie at a distance beyond $\sim$ 5 kpc.
