After all Robertson, who also assumes the mantle of assistant coach under Brett Angell on training nights at Park Island, was a made man at Team Wellington for four seasons.
There, he had led the capital franchise to back-to-back premiership crowns and three Oceania Federation Cup (OFC) finals.
Why, many would ask, would anyone trade places?
Where once he used to look over his shoulders on either side to find relative stability he now finds rookies and different faces.
Robertson will not deny he has had to deal with patches of frustration this summer but he's also enjoyed the different challenges he didn't encounter in three seasons with Wellington.
"We've got a lot of younger players in the Hawke's Bay squad who don't have as much experience as other players in the national league so, I guess, my role has been to add some value with the experience I've had and bring through those young and inexperienced players through as well."
It's not easy, he says, when the change in personnel keeps robbing the system of consistency.
"The more you play with people the better understanding you get of them as players so that's been a little bit tricky."
Nevertheless, whichever team Angell and his coaching stable have put on the park have always run out with the belief of winning games.
What disappoints him is that, had his men done their jobs a little better, those narrow losses and stalemates would have been on the right side of the ledger and their position on the premiership ladder would have been more bullish as the season hits the home straight.
"We've probably underachieved a little this season but we've probably been understrength a little as well in the last few weeks."
Robertson says it's a snapshot of the state of the code in Hawke's Bay. In order to compete to be among the top four in the country it's imperative to recruit quality players and the player base in the Bay doesn't have a sturdy foundation.
"Recruitment's a big side of it and you can bring some players in but, ultimately, you need to look at a local player base as well."
This season Bay United have brought some youngsters through to expose them regardless of whether they'll be ready for the premiership level or not. Any incremental development will put the province in a good stead in impending summers.
No doubt, a couple more experienced players or a shade more quality may have made a world of difference.
"Look at the number of draws we've had. We actually were on top and dominated and only got a point out of it rather than three," he says of the four stalemates with as many wins and five losses that have left Bay United languishing in seventh place.
With eight points left out there, that would have catapulted them into the top-four reckoning had they taken the opportunities.
"We've obviously got a lot of work to do to make the top-four from this position," he says when asked if they are hanging by the thread even if they win the remaining four games.
"It's not mathematically out of the question but with four games remaining we have to win all and hope other results are favourable to us."
He accepts the 5-2 loss to Tasman United last Sunday is perhaps the season-defining result.
It's certainly a long shot with the Canterbury United Dragons in pole position and a game in hand in fourth spot but he suspects Bay United can still influence outcomes, considering Auckland City play the Dragons in round 17 after their appearance at Park Island a weekend before.
It isn't lost on Robertson that Bay United have succumbed to all four remaining teams but sees that as a catalyst to put things right.
"It's a good opportunity for us not be beaten twice by those oppositions. Over the season we've shown we've been very close with those fine margins we haven't got right at times which, unfortunately, has probably been our downfall."
The loss of the likes of Sam Mason-Smith, Angus Kilkolly, Facundo Babero and Saul Halpin also left them toothless at the coal face, reflected in just 15 goals scored to date this season.
Robertson says Angell's bookkeeping reveals the foursome accrued more than 30 goals between them.
The franchise bears no grudges towards players who have advanced their careers, notably Mason-Smith now plying his trade in South Africa.
But the inability to fill the void in calibre left behind has proven costly.
"We've been creating numerous opportunities but we're just lacking that quality in the final third to score a goal."
Conversely the defenders don't escape scrutiny either, having conceded 22 goals to leave them with a negative goal difference of minus seven.
"We've switched off at times when we should have been more solid and, perhaps, seen more games out."
All that, he hastens to add, doesn't detract from Bay United's mission statement of winning the remaining matches.
Auckland City are the measure of any team's season and the highest standard of football in the country reserved for an exclusive crop of players fortunate enough to earn the right to savour the experience.
Although the summer cannot be classed a success, Robertson stresses the Bluewater Stadium faithful have given them a fillip at crucial times.
"It hasn't panned out how they would have wanted it to but a thank you from the players and me for that support throughout the season," says Robertson.
City coach Ramon Tribulietx told NZ Football Bay United's tactical approach made life difficult for the favourites.
"Most times they have dropped very deep and narrowed the space inside and across both defence and midfield," Tribulietx said, adding bypassing that was vital.
Former All White and Bay United midfielder Cole Peverley, who joined from Team Wellington in the transfer window, may be making his debut.
Angell said the league leaders were traditionally a difficult game.
"But I think if we go about it right, concentrate and take out the mistakes from last week, we can certainly get something from the game," he said. "But it wasn't to be and now we just have to maintain those consistently high standards, pick up as many points as we can between now and the end of the season and see where that takes us."
Transfer window winger Tinashe Marowa returns and so does goalkeeper Ruben Parker Hanks from a concussion a fortnight ago.
■ HAWKE'S BAY UTD: 1. Ruben Parker Hanks (GK), 4. Graham Craven, 5. Bill Robertson (c), 6. Alex Palezevic, 7. Wesley Cain, 8. Sam St De Croix, 11. Hayato Wakino, 12. Ben Lack, 13. Jordan Lamb, 15. Jim Hoyle, 16. Tinashe Marowa, 19. Birhanu Taye, 21. Bjorn Christensen, 22. Jorge Akers, 24. Karanjit Mandair, 26. Mackenzie Waite (RGK)
Coach: Brett Angell.
■ AUCKLAND CITY: 1. Enaut Zubikarai (GK), 2. Liam Graham, 3. Takuya Iwata, 4. Mario Bilen, 6. Te Atawhai Hudson-Wihongi, 7. Cameron Howieson, 8. Albert Riera, 11. Fabrizio Tavano, 13. Alfie Rogers, 14. Cole Peverley, 15. Daniel Morgan, 17. Reid Drake, 19. Micah Lea'alafa, 20. Emiliano Tade, 4. Conor Tracey (RGK), 26. Callum McCowatt.
Coach: Ramon Tribulietx.
