Gutsy Vale gave everything in their first game following promotion from League Two last term, but Rosler's classy team should have taken advantage of their superiority, particularly in the second half.
Rosler said: "It was a possible banana skin and I'm not disappointed with a point. I thought we did well overall.
"It was a massive pitch and a sticky surface which didn't suit us, but we controlled most of the game and should really have won.
"The potential of our play going forward is frightening, but we didn't test Vale's `keeper as much as we should have done.
"We didn't make the most of a lot of good situations we created, but it's the first game of the season and I'm confident we will improve.
"We also have to give a lot of credit to our opponents who worked incredibly hard. A lot of teams will have problems coming here."
Brentford's quality on the ball soon caused Vale problems and Adam Forshaw squandered an excellent opportunity before the visitors took a 26th-minute lead.
However, determined Vale were only behind for five minutes as skipper Doug Loft netted after his initial effort was blocked by Logan following Gavin Tomlin's right-wing cross.
Clayton Donaldson's lob went just over early in the second half after Jake Bidwell's superb pass put him in the clear.
And the visitors failed to make the most of a dominant second-half display through a combination of poor finishing and Vale's dogged defending.
Rosler was also happy with the performance of on-loan Chelsea midfielder George Saville, who grew into the game and impressed in the second half.
The Brentford boss added: "George was quiet in the first half, but this is league football and he needed time to adapt.
"He got better and better in the second half and I thought Adam Forshaw was tremendous for us in the first half."
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