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.