The Denmark international was impressed with the Scudetto holders, who dismantled Nordsjaelland 4-0 in Turin on Wednesday in the Champions League
The Danish side held the Bianconeri to a 1-1 draw at home two weeks ago, but were left without a chance in Italy on matchday four.
"We met a world-class team tonight [Wednesday]. They made us look very bad all over the pitch. It was one big off-day for us," Beckmann was quoted as saying on the official Uefa website.
"When we talked about our tactics we said the first 20 minutes were very important because they were going to put a lot of pressure on us. They scored after five minutes and again a few minutes later. It was not good for us.
"Juventus were very strong, we were very weak and the final result is the combination between those two things. They're very good at home and today they were much better than us."
Nordsjaelland sit last in their group with only one point, while Juve are are in third place, behind Chelsea and Shakhtar Donetsk.