He was confident the videotape footage, if One News were last night going to play it in its sport coverage, would absolve him of any wrongdoing. It didn't.
Okay, so what's eating Robertson when it comes to the second goal, which substitute James Hoyt tapped into the goalmouth in the 73rd minute.
Central United broke through but Stu Wilson put his noggin in the way as he directed the ball back to his goalkeeper, Jonty Underhill, but the field player had underheaded with two opposition players in pursuit.
"One of them lobbed it over Jonty to the left side of the goal where the other Central player picked it from an offside position.
"That player handled the ball before squaring it to the scorer [Hoyt] who tapped it in," Robertson claimed, adding the whistle-blower failed to pick up either infringement.
The Danny Wilson-captained Blues howled in protest but the referee waved on play and stuck with his decision.
Robertson said officials had had a hand in both goals and that was where the visitors' disappointment stemmed from.
"They have to be 100 per cent sure about things because they have had an impact on the game."
Central are now chasing their sixth title when they play defending champions Cashmere Technical, of Christchurch, in the 91st cup final on Sunday, September 7, but the venue has yet to be confirmed.
Robertson lauded his troops for "putting in a big shift".
"Another day we could have put in a goal and the result would have been different."
According to an NZ Football report, the Jose Manuel Figueria-coached Central United had executed waves of attack that led to the Rovers' defence losing its shape.
Figueria said he could not comment on the penalty incident because he didn't see it that well.
"There was a shot and a rebound and Bill was lyingthere in the middle of it on the ground.
"I was talking to him and he was saying something about how the ball was behind him so he swung away and a leg was hanging out."
On the hand-ball and offside claims, Figueria "didn't see any of that".
He felt yesterday's game was probably one of the most complete performances from Central United this winter.
"The players were focused and we stuck to our game plan as we dominated with the ball and possession to created many clear-cut opportunities."
That Central United sat on a 1-0 margin for a lion's share of the game was a little unnerving for the winners.
On Saturday, Figueria and his men had visited the nearby Waikaraka Park to watch Cashmere demolish Onehunga Sports 4-0 in the other semifinal.
"They are very well organised and a close-knit unit of eight or nine players who play together in summer, too."
Figueria said the close to 1000 fans who watched at Kiwitea St were fantastic.
"We are proud to have the opportunity to win what could be our sixth title which only one other team [Mt Wellington, of Auckland] has achieved."