Hecking's Wolfsburg rallied to earn a 2-2 draw at Napoli in Thursday's return leg but it was not enough as the Germans bowed out of the UEFA Europa League 6-3 on aggregate.
The damage was done last week after Wolfsburg crashed to a shock 4-1 defeat on home soil, a deficit that proved to be a bridge too far in the club's bid for a semi-final berth.
Speaking to reporters post-game, Hecking congratulated Napoli but said Wolfsburg were punished for their arrogance in the first leg.
"I want to compliment Napoli and Rafa Benitez, as they deserved qualification," Hecking said.
"The obstacle was probably too big for us to overcome. We played well in the first half and expected to score, but instead Napoli emerged after the break with their quality and it became difficult after going 2-0 down.
"Of course there are regrets about the first leg, as I cannot say we didn't make mistakes, even if Napoli have quality on the counter.
"In the first leg we were too confident that we could turn the early goal around, the way we did against Inter, but Napoli have other qualities and they punished us on the counter-attack.
"If we maintain concentration for 90 minutes, we can do even better than we did tonight."
With Wolfsburg out of the Europa League, Hecking is backing Napoli for the title, with the Italian club set to face either Fiorentina, Sevilla or Dnipro in the semi-finals.
"I think they have a 25 per cent chance of winning the competition. Napoli are a very good team and I hope they win," the 50-year-old added.
Thank you for reading 5 articles this month* Join now for unlimited access
Enjoy your first month for just £1 / $1 / €1
*Read 5 free articles per month without a subscription
Join now for unlimited access
Try first month for just £1 / $1 / €1
Get FourFourTwo Newsletter
The best features, fun and footballing quizzes, straight to your inbox every week.