"I was very scared. You don't have too many possibilities to win the race in this way, especially if you are not explosive and don't have the sprint like Philippe. I was in a good position there and I had to push all the watts I had. Luckily it was enough."
The BMC rider attacked fellow breakaway companion and Australian David Tanner (IAM) with less than four kilometers remaining to take his first win since 2011.
Hermans and Tanner co-operated 33km from the finish after the break of the day was nullified and never held more than a 33 second lead on the chase group.
Tanner was swept up by the peloton as he approached the finish while Matthews (ORICA-GreenEDGE) led the chase home to finish second ahead of Herman's team-mate Philippe Gilbert.
"I think the race was pretty hard in the beginning, but I was going good in the wheels and saving energy," Hermans said. "I have done this race several times and suffered more in the beginning, so I knew I was good. I also told Philippe that if I have to go in a counter attack, you need to tell me - or if I have to make the race hard. Luckily, it turned out good. Everything was in the right place for me to win the race."
De Brabantse Pijl: 205.4km
1 Ben Hermans (BEL) BMC 4hr 45min 14sec
2 Michael Matthews (AUS) Orica-GreenEDGE 0:00:02
3 Philippe Gilbert (BEL) BMC Racing Team
4 Tony Gallopin (FRA) Lotto-Soudal
5 Davide Rebellin (ITA) CCC Sprandi Polkowice
6 Nathan Haas (AUS) Cannondale-Garmin
7 Fabio Felline (ITA) Trek Factory Racing
8 Maurits Lammertink (NED) Roompot Oranje Peloton
9 Maciej Paterski (POL) CCC Sprandi Polkowice
10 Dries Devenyns (BEL) IAM