Harrogate CC captain George Ross struck a century as the Roosters beat Acomb by 76 runs to secure a third consecutive ECB Premier League North success.
The hosts managed to compile 274/5 from 50 overs batting first, before bowling their visitors out in the final over of the match to wrap up maximum points.
Ross made exactly 100 at the top of the order, registering his first ton in the league for 2017.
Tattersall weighed in with a quick-fire knock of 73 and Atkinson then struck 60 not out to guide ‘Gate to a more-than-useful total.
In reply, Acomb were unable to keep up with the required run-rate and went into the last over on 198/8.
Two wickets in the space of three balls then saw them dismissed for 198 and the Roosters snap up 10 points.
Kallen Bond was the pick of the visitors’ attack with figures of 3-45, while Stow (2-26) and Ross (2-44) also impressed.
Victory sees ‘Gate climb one place to fourth in the league standings with three games remaining, the next of which sees them travel to Clifton Alliance on Saturday.