"For most of the time we were in the lead, we controlled the game, we created more chances than them," Skrtel told SITA. "Petr Cech did perfectly for Chelsea and we, instead of winning 3-0, managed to claim just a 1-1 draw.
"Everything is still open, there are 90 minutes to be played.
"They are up now but I firmly believe that we have the potential to score a goal at Stamford Bridge. And if we don't concede, we will go through - the cup mathematics is as simple as that.
"Everything will come clear on the pitch and I am convinced it will turn out well for us in the end."
Skrtel refused to blame Riise for his own goal and admitted he was shocked in the manner of how Liverpool conceded so late on when Riise headed Salomon Kalou's cross into his own net.
"It was a big shock and disappointment for me," added Skrtel. "Nobody at the stadium expected anything like that as it were the last moments of the game.
"After Kalou's cross two of us defenders were in front of the goal and I was the one to defend Drogba. The ball came to the far post, Riise wanted to head it over the goal or out of the pitch but he did not manage to do that.
"But that's football, such things happen. It is a pity. There is still the second leg where we can undo this stumble."