The PSV winger was delighted with his side's victory, and urged his team-mates to carry their good form into the World Cup qualification campaign
The PSV star came off the bench halfway through the second half, with the Red Devils trailing 2-1, but single-handedly turned the game around by scoring once and setting up two more to help his country to victory.
"The most beautiful moment was the goal that made it 4-2. At that point, you know it is in the bag," Mertens told the official Uefa website.
"Scoring is nice, but realising you are going to beat the Netherlands is also very special."
The winger then went on to add that Belgium have not achieved anything yet, and is keen to help his team-mates replicate Wednesday's performance throughout the World Cup qualification campaign.
"We have not won anything yet. On September 7, we will be there to do the job. We know we have to do it now, and that we have to be on the ball from the very start."
Belgium lock horns with Wales in their first World Cup qualifier.