Pompey were second best for much of Saturday's 1-1 draw in League One at the Ricoh Arena and trailed to Gary McSheffrey's well-taken opener after 41 minutes, but they battled to the end and snatched a point when Izale McLeod capitalised on hesitant defending to stab home from close range.
McGoldrick thought he had added a second in the 88th minute when he tapped in the rebound after Carl Baker had hit the post, but it was ruled out for offside.
Robins said: "If they hadn't made any changes in the second half then you would have been asking questions because we had absolutely battered them. We passed it well, we passed it with a purpose and I was delighted with the goal. It was a great run and great goal from Gary McSheffrey.
"The goal that we scored and had chalked off, there is no way on this planet that it was offside. I have looked at it twice, but I didn't need to.
"McGoldrick is two yards onside, it's hit the post he's controlled it and put it in the net but it's been disallowed. I'm really disappointed with that because we have done enough to win it. I was disappointed not to get the three points because we were almost there."