Chelsea indeed got a bit unlucky at times since their goalscorer missed big chances or made some stupid decisions, but you can't blame luck if your opponent made 9 saves to prevent you put the ball in the net. You could even say the same about Liverpool since they hit the goalpost twice iirc, and Elliot nearly won them in the ET too since the ball is just millimeters from passing the goal line.
In a football match, result is all, if you can score goals to win it or create enough pressure to force your opponent players to make mistakes and conceded goals, you succeed and are the winner. If you dominate the match, has high ball possession but fail to score goal, you will get a draw but worse, let the opponent to beat you from a counter attack.
Liverpool generally played and deserved to win Carabao Cup but Chelsea have reasons to think they deserved more. It's part of fact and shows their potentiality to be a stronger team and they can move forwards with this motivation but most important, must improve themselves more.
More accurate shots, more calm mental to make proper decisions and avoid mistakes. They have star players and young players who can grow up more and contribute more for them in next several seasons.