The childhood Newcastle United fan returned to first-team action in the 83rd minute at Bramall Lane, more than three months since her last appearance in United's Tyne-Wear derby victory over Sunderland Women.
However, while Furness was delighted to get on the scoresheet and be back out on the pitch, she couldn't hide her disappointment after the full-time whistle.
"We found ourselves 1-0 down late into the game, so we have to see it as a point gained," the Northern Ireland international said.
"It could've easily been a defeat, so we've got to look at it from that point of view, but we're disappointed overall.
"I'm not sure what it was; I think we just didn't move the ball quickly enough and with enough quality, which played into Sheffield United's hands with their press, and it's something we've got to work on.
"It's a dream come true to score for Newcastle; I just wish it was the winning goal because I think I would've ended up jumping into the crowd to celebrate with them."
Furness, who spent four years with Newcastle at the beginning of her career, decided to return home in the summer and has always dreamt of netting for United.
Now that the 36-year-old has achieved that, she's eager to play a big role in the second half of the season, both on and off the pitch.
"We never give up; we'll always fight for the badge no matter what happens," Furness admitted.
"I was limited to only ten minutes (on Sunday), albeit I think I got a little bit more with the added time at the end, but for me to be back in the squad and around the girls on match day is a fantastic feeling.
"Now that I've had that feeling of scoring in front of our fans, I want to have that over and over again.
"I know how much I can give on and off the pitch for this club, and I'll always look to do that."
Tickets for Sunday's Women's Championship game at Kingston Park against Portsmouth Women are on sale here.