Jardim's men could not find a way through a stout Benfica defence in an uninspiring Group C clash at the Stade Louis II.
Benfica were thwarted on a number of occasions by goalkeeper Danijel Subasic at the other end in the second period before being reduced to 10 men when defender Lisandro Lopez was shown a straight red card for a foul on Joao Moutinho.
However, Monaco's numerical superiority made little difference in a turgid encounter, leaving Jardim to bemoan his side's deficiencies in the final third.
"We really wanted to win. We had a good first half but we didn't convert it into control of the game," he told beIN Sport.
"Then the game was balanced. We pushed to the end but without success. It is difficult to maintain the same level for 90 minutes.
"I am not happy with what we have shown with our offensive level, even if we still had a few opportunities."
Monaco will have the chance to atone for their below-par performance when they visit Benfica in the return fixture in two weeks' time.
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