Wairarapa edged out the Fergus Neil-captained Rovers 4-3 in their Central league encounter here on April 17 in their only game so far this winter.
"The players are already looking forward to it," said Robertson.
His men were leading 1-0 against Wairarapa until the heavens opened at halftime to swing the momentum in favour of the visitors who had adapted a "direct" approach much quicker than the hosts.
"To be honest it turned into a bit of a lottery so we were a little disappointed because we were quite comfortable [until that stage]."
However, he said a lot of water had flowed under the bridge since for a team who had the resources to recruit elite players.
Robertson said some of the marquee teams had byes into the first two rounds and some played lower-tier oppositions but although the Blues didn't enjoy that they accepted it was the luck of the draw and had to come to terms with it.
"Hopefully there'll be a good crowd."
Petone play Suburbs, Miramar Rangers face Tawa and Stop Out host North Wellington in other cup matches in the catchment area.
A resurgent Rovers play league leaders Western Suburbs away this Saturday.