Josh Stevenson struck in the 7th minute but Wairarapa's Thomas Hemi levelled terms, 1-1, almost immediately.
Rovers midfielder Ryan Tinsley made it 2-1 in the 21st minute from a penalty kick before right-mid Fergus Neil extended it to 3-1 two minutes later.
Welsh import Miles John scored in the 41st minute.
At halftime Robertson told his troops not to change much because of their ascendancy, keeping imposing striker Hamish Watson on a leash.
"In the second half, a little bit of complacency probably kicked in," he said.
"We were very complacent and very slow and gave them too much space, allowing them to control the game."
In a nutshell, golden boot leader and Wellington Phoenix sqaud member Watson scored a penalty in his hat-trick of goals in the space of 15 minutes to level, 4-4.
Said Bay-born Wairarapa centre-mid Tom Biss: "They [Rovers] looked after Watson pretty well in the first half."
When they refocused on Watson it freed up Biss to claim his hattrick, too.
"At halftime we were pretty down but if there's one thing we do is play right to the end no matter how many goals down we are.
"We said we'd go out there for the next 45 minutes to empty our tanks," said Biss who finds out in a fortnight if he's going to play for Kinetic Electrical Hawke's Bay United again this summer in the ASB Premiership.
"We've got to the end of the season now but Rovers have two more tough games," he said of the Blues' two home games against 2014 league champions Miramar Rangers and second-placed Western Suburbs.
Biss and his captain/defender, Adam Cowan, were named in a Central League Select XI to play against the Wellington Phoenix at Weka Park, in the Kapiti Coast, in a 2pm kick off this Sunday.
Robertson said Wairarapa were capable of scoring eight to nine goals with high-quality individuals who caused them problems.
"We made some personnel changes but we don't want to make too many excuses as all the players are good enough to play at this level."
Matt Hastings pulled out with an injury after warming up.
Phil Dol played leftback, Josh Anstis was rightback and Bayley Chadderton slotted into Robertson's centreback position.
Oli Chapman was in Chris Greatholder's holding midfield role while Stu Wilson was in the place of striker Angus Kilkolly who was serving a match suspension for five yellow cards.
Wairarapa 7 Rovers 4