Hecking was taking charge of Monchengladbach for the first time in the Bundesliga and things didn't go well in the first half as goals from Jonathan Tah and Javier Hernandez put the hosts 2-0 up at half-time.
Something changed though as in the second half the Foals were much improved and got their rewards for stepping things up and two goals from captain Lars Stindl and Raffael gave them a massive win which should kick start their season.
Both sides missed early chances
The start of the game was pretty even with both sides having early chances to take the lead in a crucial game for both clubs.
Firstly, Charles Aranguiz forced Yann Sommer into making a really good save after he headed the ball towards goal from a well delivered corner.
The visitors then had a chance of their own when Mahmoud Dahoud found himself in space in the box but saw his fierce low shot well saved by Bernd Leno.
That is when the visitor's though started to go off the boil in the game and allowed the hosts to start putting them under more pressure.
Two goals in three minutes gave the hosts 2-0 lead at half-time
This lead to the opening goal of the game as Tah headed home his first goal for Leverkusen from a brilliant Hakan Calhanoglu corner just after the half hour mark.
It didn't take them long to double their lead either as three minutes later, once again from a Calhanoglu corner, Hernandez scored his first Bundesliga goal in 11 matches after a good flick on by Karim Bellarabi at the front post.
After going two goals up, the confidence of the hosts was clear to see as they continued to pile forward and went close to making it three when a lovely move ended with a curling shot from Kevin Kampl from the edge of the box just going wide of the goal.
Therefore, the Foals were more than happy to get in at half-time only two goals round knowing that they would need to play much better in the second half or this game could get even worse for them.
They improved massively in the second half and they should have got a goal back within three minutes of the restart when a great cross found Thorgan Hazard one on one with Leno but the keeper kept the winger's shot out.
Stindl struck twice in six minutes to get the visitor's back on level terms
The miss didn't matter though as not long after that the visitors did get a goal back through their inspirational captain Stindl.
Stindl created the goal by himself as he outmuscled Tah off the ball and unleashed a great right footed shot from the edge of the box into the top corner of the net.
From there, the Foals momentum grew and they got back on level terms just before the hour mark when a well worked goal ended with Stindl netting his second goal of the game as he headed home Oscar Wendt's cross.
The hosts were shell-shocked by the visitor's performance in the second half and they just couldn't get going at all and that meant that they gave encouragement to the visitors and they took it.
Raffael's superb solo goal completed impressive comeback for Foals
The Foals completed the comeback when Raffael scored a brilliant solo goal with 19 minutes to go to put his side in front after being 2-0 at half time and every single player in the team celebrated the goal.
The hosts failed to respond to that which will not go down well with their manager Roger Schmidt, who wouldn't have seen that second half performance from his team coming.