The Hoops passed up on the chance to leapfrog their Old Firm rivals at the top of the table on goal difference last night when they could only draw 1-1 with Kilmarnock at Parkhead.
It was their third successive home draw and kept Neil Lennon's side two points behind the Light Blues, who have played a game less.
It might have been worse had Rogne not headed a late equaliser, his first goal for Celtic, after Killie striker Conor Sammon's solo goal in the 54th minute had given the visitors a shock lead.
"We have drawn three games and we should have won this one," the 20-year-old Norwegian defender said.
"We are too soft. We concede stupid goals and we don't finish it off when we should.
"Just as much as we gave away an easy goal, we were not able to score. We had plenty of chances and they basically had nothing. They scored from a counter-attack from our corner and that should never happen.
"My goal doesn't matter other than it's a point for us.
"We wanted to be top of the table at Christmas but we lost two points so we are disappointed with the result.
"The performance was better than the last two so we have to look on the bright side, that was good, but the performance doesn't matter if you don't win."
Lennon watched Gary Hooper stretchered off before the interval following a tussle with Killie defender Frazer Wright and hopes a scan this morning will not show a broken fibula along with suspected ankle ligament damage.
The Celtic boss admits the injury is a huge blow and will see him move to sign another striker when the transfer window opens in January.
Kilmarnock boss Mixu Paatelainen saw Sammon score his 15th goal of the season but admits he is all but helpless to prevent the Irishman leaving if the cash-strapped Rugby Park club receive an offer.
The Finn said: "All our players might leave in January if someone comes in and offers money. They are all for sale. I don't think anybody is there forever. If the price is right and the chairman says yes then it happens."