Johnston moved up to second in the table after defeating bottom-placed St Ishmaels in the Manderwood Pembrokeshire Football League First Division.
This was the only game played in the first division as most of the other teams were playing in the West Wales Intermediate Cup, where the Tigers are the holders.
Johnston are playing in the competition but they had a bye and will now come into the competition in the second round.
The Tigers found Tish a tough nut to crack and did not break the deadlock until the 60th minute and then bagged three further goals in the last six minutes as Tish ran out of steam.
Nicky Woodrow scored a hat-trick; the striker has now remarkably scored 18 goals in the eight matches for Johnston after signing from Welsh League Division One outfit Haverfordwest County.
To catch up with how our Pembrokeshire teams got on in the West Wales Intermediate Cup go to our latest news section on the home page to find out the results.