Rovers teenager Angus Kilkolly drew first blood in just the sixth minute after a wave of attacks from the kick off when John put in a superb cross in the money box from the left flank to the striker who deftly placed it in the net past goalkeeper Graham Healey.
John was a thorn in Taradale's side despite receiving some attention from the experienced defenders, verbally and physically.
Taradale's equaliser came in the 55th minute from Dean Johnston after they broke through the middle to pass the ball to player/coach Chris McIvor, who ran up the right flank before crossing for Johnston to bring it down and push it past goalkeeper Kyle Baxter.
Controversy No 2: Did Johnston use his hand to bring the ball down to heel?
Robertson said: "It was a blatant hand ball. He used his arm to control the ball and put it into the net."
"The ref obviously didn't see it and neither did his assistants."
McIvor said: "I honestly didn't see it because I was too far away.
"There was a lot of controversy in the game because it was a classic derby. If they want to talk about it then there's a lot of things to look at."
On the Blues' penalty, McIvor said the collision was common at premiership level.
"It wasn't a penalty. It was gut- wrenching for us," he lamented but accepted going into extra time would have counted against the older Taradale legs.
Having watched Rovers play Tawa in their Central League clash at Park Island late last month, the Maroons' game plan was to inject more physicality considering the Rovers had a tendency to push players higher, thus making their defence vulnerable.
"Our experience told and we'd done our homework."
Robertson said there was transparency in Taradale's game plan and the bulk of former Rovers cup and national league champion players had executed it with aplomb.
"If I was in their situation I would have done the same so I can't fail them for it.
"They are two divisions below and they made life difficult for us so we're just delighted to be in the next round."
He said the Danny Wilson-captained Rovers were now focusing on a tough Central League match against Wairarapa United this Sunday in a 2pm kick off at Bluewater Stadium.
Wairarapa, with former Hawke's Bay United pair of Tom Biss and Hamish Watson, yesterday thrashed lower-tier Marist (Wellington) 11-0.
In Masterton, the Murray Group Havelock North Wanderers, with Bruce Barclay as coach, thumped Douglas Villa 6-0.