Riis’ goal made it 2-2, in the 95th minute, the second time that PNE had come from behind in the game against Bristol City.
Chris Martin had put the visitors in the lead in the first half before Riis opened his account on the day, converting a rebound from Cameron Archer’s long-range strike.
Antoine Semenyo put the Robins ahead again with less than 10 minutes to go, only for PNE’s top scorer to acrobatically draw them level.
It was a wonderful move that started with a crucial tackle from Ali McCann and ended with a lung-bursting run from Brad Potts to supply the cross for Riis’ goal.
Riis said:“It was a great goal to score and it was great to save a point for the team but there was a lot of hard work before that and I’m happy to help the team in the end.
“That’s why I’m here, to score goals. It’s your role in the team to score goals. Last Wednesday I got a very easy one so I’m happy to show I can score different types of goals.
“I’m happy to score one like that. I saw the long ball to Brad Potts and he had to run a long way to get it – it was a great cross and Ched Evans in front of me was a great decoy.
“When I hit it, it was just about hoping and believing, I heard Andrew Hughes behind me but I took the chance myself.
“I have a lot of confidence and I take the chances when I get them. Luckily, it went in. I do like a late goal, it’s nice to change the result in the last minute.”
Despite taking his tally to 16 in all competitions this season, goals were not the only thing on the 23-year-old’s mind.
Riis felt that North End’s performance improved as the game went on and felt sharing the points was fair.
“It was good to get the goals but obviously we would have liked to have got three points,” he said.
“In the first half we were not great and we changed a few things at half-time, we played around and got a lot of chances.
“I thought in the second half we were on top, we got the early equaliser but unfortunately they got one chance and they scored.
“We had to chase the game again but we came back twice so a point is okay. We were behind two times, to come back both times is good.
“It’s not good to go behind but we had good belief in ourselves and kept going. That’s how we’ve got to play every time.
“A point is fair enough, we were really bad in the first half and were better than them in the second half.”