Bay United coach Chris Greatholder's men found cohesiveness, stringing passes to work their way into scoring opportunities while Wellington did mostly that in the middle of the park but seemed bereft of ideas in the final third.
Perhaps the only distraction for the Bay was Dakota Lucas, making his debut at home against his team from last summer.
While his surgeon from Royston Hospital in Hastings would have been cringing if he was on the sideline, Lucas delivered with aplomb right up to when Greatholder substituted him just before added time kicked in.
The 21-year-old had said pre-match he didn't intend going out too hard after keyhole surgery to his right knee only a fortnight ago, and that discipline prevailed.
Instead he took deft touches, made incisive runs and fed the ball to English import Stephen Hoyle.
In the 14th minute, Lucas nodded in a Robertson freekick to put the hosts up 1-0 after Wellington's Luke Gulley fouled.
Two minutes later rightback Gulley once more assumed the mantle of villain, this time bringing down Bay midfielder Conor Tinnion in the 18m box on the left flank.
Cole Peverley casually planted the ball from the magical spot past Wellington keeper Scott Basalaj to extend the lead, 2-0.
It wasn't until the 65th minute that Tinnion questioned the worthiness of the Wellington defensive wall after a fleet-footed Lucas drew a foul at the edge of the 18m box.
Tinnion curled the freekick past keeper Basalaj from an obtuse angle for a 3-0 lead to effectively kill the game because the visitors, who raided the Bay goalmouth for a good 15-20 minutes, failed to finish time and again.
"We have a clean sheet and as a defender I pride myself in that and I know a lot of our boys do too, in keeping that defensive shape," Robertson said.
He was equally appreciative of his men's attacking third for finding the net on the other end of the park at pivotal times.
It didn't bother him that the Bay hadn't won against the capital city slickers at home in previous premiership encounters, and that they had broken that hoodoo yesterday on a season's campaign to secure a maiden play-off berth for the franchise.
"We know the record wasn't that flash but we didn't read too much into that because it's all about this season and we have a good squad who are confident of taking three points on their own pitch.
"Just when we lose a striker through suspension [golden boot contender Sean Lovemore] DK's looking all right and he's got himself a goal today so that's timely for him but also Jarrod Smith's not too far away, either," Robertson said as Smith recovers from a niggly injury and has yet to run on to the park this summer.
Going into a three-week Christmas break before the second half of the season, Robertson was looking forward to competitive trainings sessions for the starting berths as the balmy weather also made a showing in the Bay.
Hoyle, he said, had a couple of goals but also worked hard off the ball to create chances for others to offer the franchise four quality strikers for two spots.
The squad won't have a complete break but Robertson assured fans the players would look after themselves in the festive season.
Wellington had former Bay United academy player Tom Biss in the engine room and ex-Bay United player Hamish Watson, although the striker was barely noticeable.
It is perhaps indicative of the gulf between the Central League in winter, where Watson was a goal-scoring machine, and the premiership where there's a paucity of time to think, let alone move.
Wellington defenders Luke Rowe and Alec Solomons displayed immense skill and composure to show why they are in contention for Wellington Phoenix contracts but Bay United should have scored more goals with Aaron Jones, Hoyle and Tinnion's efforts missing the target.
Wellington coach Matt Calcott said it was imperative his team "have got to get away from just playing for the sake of playing a little bit". "We're developing positions where we're passing the ball but we're not ruthless enough," Calcott lamented.
He didn't think his men defended with the vigour and passion of Robertson and his Beefeaters.
"Hawke's Bay has some old-school centrebacks who want to head the ball and they want to get out and get to the ball.
"You know, that's what's lacking because there's no point in playing football for football sake."
Calcott said while his players were young it was part of their curriculum to find that mental fortitude and learn from their mistakes.
"You know there were a couple of times when they could have defensively done a couple of things a little better - and we've done that a couple of weeks in a row - so that's something we've got to put a line through to do better next time.
"Yes we've got some talented footballers but at 19 and 20 part of it is to learn how to win matches and at the moment we're just not doing it."
That the A-League Phoenix squad didn't train with the Team Wellington players didn't help and could change.
"We've had some successful teams in the past and you know the recipe is to work hard as a group," he said but didn't want to use that as an excuse for their recent poor patch.
"I don't think we should make too many excuses for these guys today because they want to go on to bigger and better things so we need to say, 'Right, stake in the ground. Whatever it looks like when you go on the ground you've got to make sure you perform', but some of them haven't done that today."
Despite coming off two successive losses to high-flying Waitakere United and Christchurch United, Robertson's men should provide more sizzling matches over summer after the Christmas break when they host Waikato United on January 13.