"I would have liked to score more goals because we had a lot of chances but we only took two of them, which is slightly disappointing," Robertson said, before the Blues travel to Auckland for the Chatham Cup (knockout) semifinal against Central United on August 17.
On the flip side, the centreback saw it as a bonus that they had created numerous scoring opportunities.
"It was a good three points because they're a reasonable side and it could have been a tricky game for us so to get another win at home was pleasing."
Robertson lauded young goalkeeper Jonty Underhill for making a couple of crucial saves and creating chances on the breaks.
A grinning Robertson momentarily reflected on not having to go to his bench to inject substitutes in the game.
"At the time it was a tough game and we defended well for 15 minutes or so.
"Sometimes I believe changes can hinder you rather than be a benefit in terms of communication and breakdown with someone coming fresh off the bench because he's probably not up to speed with the game so I didn't think we needed to make any changes because we were pretty comfortable about seeing the game out."
The Rovers went up 1-0 in the eighth minute when Marist goalkeeper Gurkanvir Singh failed to thwart a shot from striker Angus Kilkolly.
In the 60th minute Andy Bevin had Blues fans singing and the muted Marist women Fed Cup players deserting the stands with a great header from inside the box after a deft curling cross from Stu Wilson for a 2-0 lead.
In the 79th minute Marist centreback/captain Fin Milne pulled one back to 2-1 after nodding in a cornerkick.
Josh Stevenson could have put the game to rest two minutes later after substitute defender Woody Maxey-Graham duffed a pass back to the keeper but Singh denied the fellow policeman.
In three minutes of added time, Stevenson had another chance from the left flank but his drive cruelly clipped the bottom right upright and ricocheted back into play.
The Rovers travel to Wellington to take on Petone AFC this Saturday.
Palmy Marist coach Simon Lees said his team had sat back early because not doing it had cost them in previous games.
"Tom was out today so that was probably a big loss to us," he said of 2013-14 Kinetic Electrical Hawke's Bay United striker Thomas Mosquera, lamenting a lack-lustre final third.
Marist, he said, often took a direct route because playmaker Tyson Brandt sat behind the two strikers.
Their goals often came through an "outstanding " Brandt who had a solid rapport with Mosquera.
That stance, Lees said, also kept the Rovers defence in check, making it harder for them to build attacks.
"They caught us on the break in the first one and in the second one the ball was knocked down and we didn't clear it."
The bank officer wished the Blues all the best in their Chatham Cup play-off.
In the other matches, Western Suburbs upset Miramar Rangers 7-1, Upper Hutt and Petone drew 4-4, Wairarapa United beat Lower Hutt 4-2 and Wellington Olympic beat Tawa by the same score.
