The Reds took a while to kick into gear at Hindmarsh Stadium before eventually putting the hapless Glory away 2-0 but not before some strong words from their Dutch coach at the half-time interval.
"I think sometimes it's your job to do it," Coolen said yesterday of his half time tirade.
"That happens sometimes in the season, it is not the first time, but yesterday was definitely one of them, yes.
"We spoke a lot about the first half this morning because that wasn't good enough, but it's good for a team if you can change that during the second half.
"If you play a real bad first half but can change it in the second half the way we did yesterday, that's also a sign that we have a good team.
"A team needs confidence and the easiest way to get confidence is winning games. I was real happy with the way we played the second half, that's the way we prefer to play."
Coolen will be hoping his Reds are right on top of their game when they take on bottom-placed Newcastle Jets at EnergyAustralia Stadium tomorrow night.