Second-half goals from Jurgen Locadia and Luuk de Jong helped the Eredivisie champions to the full three points and Hecking said Wolfsburg did not deserve more.
"We were very good in the opening 30 minutes, but we then made life hard for ourselves," Hecking told reporters.
"Overall this was simply not the kind of performance you need to get a good result on the European stage. Conceding a second goal was very annoying.
"We lacked determination and power going forward and hardly created any chances.
"I think PSV deserved their win." Tuesday's defeat saw Wolfsburg drop to third spot in Group B with six points from four games, level on points with second-placed PSV.
But Hecking feels nothing has changed with a view to potentially reaching the knockout stages.
"Our task very much remains the same. We now have to get something from the away game against CKSA Moscow," he said.
Wolfsburg travel to Moscow on November 25, before hosting Manchester United on December 8 on matchday six.