The Spanish side dropped out of the Champions League after finishing behind Juventus and Manchester United but possessed the cutting edge required to damage Celtic's hopes of progressing in the competition.
"The lessons are you need to really concentrate, there wasn't a lot in the game", said Rodgers.
"We have to learn from it, we have a lot of young players, and next week if we can get the first goal it can bring a different possibility for us".
Callum McGregor lost possession in midfield as Valencia broke the deadlock on 42 minutes, with Emilio Izaguirre playing the galloping Sobrino onside in the build-up.
Now Celtic must improve on a poor away record in Europe if they are to overturn the two-goal deficit at the Mestalla in next week's second leg.
"We started the game very well. When you do that against good teams it kills your momentum, puts you on the back foot".
"At times we lacked concentration, which is so important at this level, and Valencia were pretty comfortable by the end". So it ended up a disappointing night for us.
It will be intriguing to see how the Hoops go about the second leg of the tie. We had good control and pressed the game. It did look as though Burke was set to break free of his shackles towards the end of the first half when Scott Sinclair sent him scampering in behind the Valencia defence, but stopper Neto raced from his line to clear before he could get a strike away.