Robertson said the Rovers had played Stop Out three times this winter and in the last two games the hosts had made life difficult for them. The Rovers beat Stop Out 2-1 in a Chatham Cup match at Park Island last month and 3-1 at the same venue early in the season.
On Saturday, he felt Stop Out had created half chances when the Blues led 2-1 but his "lads had pulled themselves together to hit the road with three points".
The visitors went up 1-0 from an Angus Kilkolly penalty kick in the 17th minute after a defender brought down Josh Stevenson in the box.
It was not until the 71st minute that centre-mid Tom Biss made it 2-0 from a freekick but Stop Out struck back almost immediately, when Micky Malivuk nodded the ball in from a counter-attack.
Midfielder Ryan Tinsley pacified the hosts with an 89th-minute goal from the edge of the box.