The goalkeeper had kept out Harry Kane's first spot-kick of the match, awarded shortly after the visitors had equalised, but could do nothing about a well-struck second that cancelled out Mohamed Salah's brilliance in injury time.
A draw ensured the Reds remain in the top four with a two-point advantage over Mauricio Pochettino's team, but Karius was left disappointed at not having opened up a bigger gap.
"To me, it doesn't feel good at all, I don't know if it's fair or not," he told Liverpoolfc.com.
"I just came in, I didn't see any replays but some say it's very harsh; the first one, offside maybe, the second one, the referee says no and the linesman waves his flag.
"As a player, it's hard to believe what just happened. You score a goal so late and everyone thinks you've got it and then you have to take a point. If you look at it before the game, one point would have maybe been better for us than for them, but if you look at it after we lost two and they won one.
"We could have been five [points] in front so right now it's still hard to take positives out of it."
Karius also revealed that his spot-kick save from Kane was down to his pre-match study of the striker's technique from 12 yards.
He explained: "I [didn't] just stand up, I watch the strikers before the game.
"I knew he was the number one penalty taker so I looked at it and it felt like in the big games he tended to go a bit to the middle.
"So I made the decision to stand up in the middle and react and it paid off. You have to get a bit of luck sometimes but have a better chance if you look at it like this."
The 24-year-old was happy with the way Jürgen Klopp's men defended during a second half that saw Tottenham on top, insisting the quality possessed by Sunday's visitors made it inevitable that they would control periods of the game.
But he believes there was an element of fortune in both of Spurs' goals in the end.
"Of course, they were a bit on top in the second half, they really, really needed to get a result," he continued.
"Even if we were a bit tucked in, that's how you have to be sometimes, Tottenham are a good team. We defended well and then got very unlucky, they scored a wonder-goal and there's not much you can save there.
"Maybe if you just look at all the chances, it's fair, but with the end we have to take a point."