Alan Stubbs felt his Hibernian team deserved something from their Scottish Championship match, which Edinburgh rivals
His striker Farid El Alagui scored in the final minute of normal time but by then Sam Nicholson and Prince Buaben had scored for the hosts.
"Anyone who watched the game would come away thinking we didn't deserve to get beat," Stubbs told BBC Scotland.
"I don't think the scoreline reflected the game."
The match looked as if it might end goalless after Liam Craig had screwed a first-half penalty wide and there were very few attempts on target.
However, Nicholson cracked a shot beyond Mark Oxley in 76 minutes to send those in maroon into raptures and four minutes later Hibs midfielder Scott Robertson picked up a second booking and was sent off for barging into Prince Buaben in the penalty box, a move that was further punished when the Ghanaian scored from the spot.
"We showed some really encouraging signs today," continued Stubbs. "We've come a long way in a short space of time.
"At times when we did pass it we looked decent enough but it's all about results and I didn't think the result was warranted.
"We need to turn performances into results. I want the mentality to be even stronger. We need to really hate getting beat.
"It's an ongoing process. We will look to strengthen if we can."
Robertson was not the sole player to be red carded by Willie Collum. The referee also showed a straight red card to Osman Sow for elbowing Hibs defender Michael Nelson as they contested a high ball.
There were six other bookings, two of which were for Hibs players David Gray and the skipper Craig.
"I think our lads controlled ourselves well," said the Englishman.
"When you look at their sending off I think it's a really poor challenge. I thought he did it once or twice before that and he got away with it.
"It's something that we don't want to see. I don't think he's got any excuses.
"A bit of ill-discipline has probably cost us. It's a local derby. Sometimes it can affect the players. They get caught up in the moment.
"The penalty was a penalty. It's disappointing."