Plasil admitted that Benfica's goals came at bad times during the game but that Bordeaux could use the attacking performance as a benchmark for how to play for the rest of the season.
"We played a solid game with a lot of desire and attacking intent, but we conceded the first goal too quickly and that killed us a little bit," UEFA.com quotes Plasil as saying.
"We managed to equalise and started to believe again, but then we conceded the second goal. After that, it was basically mission impossible as we would have had to score four or five.
"The performance was reassuring, given the high level of the competition, and it would be good to be able to repeat it over the rest of the season."
Plasic has 80 caps for the Czech Republic.