The 48-year-old was philosophical after watching his side draw 1-1 on Thursday night
Rubin grabbed the lead 15 minutes into proceedings via Marko Devic, but Emre Can restored parity in the 37th minute, immediately after Rubin defender Oleg Kuzmin was sent off.
"It wasn't a masterclass but it's not the worst day in my life," Klopp said post-match.
"It wasn't a boring game. It was a very interesting game, a big challenge because of the quality of Rubin Kazan.
"Everybody could see they are not too bad – very experienced, very cool when they got the ball. They didn't have it too often but when they had the ball they were really good.
"They got the first goal and that's one of the biggest challenges in football. You are in a good moment, your direction is OK, you're in the game, your concentration is high and you're playing football and you have this. You need to restart in the game but we did it well and got our goal.
"Before that they got the red card. Sometimes it's a big advantage against 10; most of the time it's a really thankless job because now they stop playing football. Now they defend in a big, compact block."
Liverpool sit second in Group B following Thursday's results with three points from as many games.