After an absorbing two hours of football saw both teams have goals disallowed in a scoreless draw, the first 21 kicks of the penalty shoot-out were successful, before Kepa hammered his over the crossbar to hand Liverpool a first domestic cup since 2012.
The Spain international had replaced Edouard Mendy from the bench deep into extra time with the aim of winning Chelsea the shoot-out, having excelled in the same scenario during a Super Cup victory over Villarreal last August.
Although Kepa's terrible penalty sailed into the Wembley stands to deal Chelsea their second domestic cup final loss under Tuchel, the German refused to apportion any blame to his player after the match.
"I feel bad for him but [there is] no blame", Tuchel said. "If you want to blame someone, blame me. I take the decisions and I don’t take them to be the hero.
"We took the decision like we did last time [in the Super Cup] in the penalty shoot-out.
"Everybody knows how good he is. Unfortunately, he could not save the penalties, which were brilliantly taken."