The four stage men and women's competitions were won by Logan Giddy and Janine Kavanagh respectively.
McDowell was a first time winner of one of the series events.
After competing at cross country overseas while in his teens, now 23, he has only just recently started riding again.
"I only started doing enduro this season, so I'm pretty stoked to get there," he said.
"I raced cross country all the way through school and raced overseas for a bit, but from there I sort of gave up cycling for a while. I did a building apprenticeship and a few other things and rode motorbikes for a while. But a few mates were racing enduro the whole way through so I bought an enduro bike and started getting into that and now I'm looking forward to carrying on with that really."
McDowell missed the first of the four round Giant 2W Gravity Enduro series, but competed in the second and third and also in the Enduro World Series round that was part of Crankworx.
"I had a few good stages, but like a lot of people during that race, I had a crash and bent the handlebars and lost a lot of time there and that put me out of it - but I gave it a good nudge."
McDowell said his progression to round winner was down to his increasing fitness and his liking for Saturday's course.
"I'm gaining a little bit more experience in the sport after being a rookie earlier on and the course suited me over the weekend as well with a few of the tracks that were thrown in.
"There was a bit more pedalling involved as well and as I'm from a cross country background that an my fitness kicking in helped."
He had one off, at the top of Corridor.
"I wasn't injured and didn't break anything so I went back up and re-rode it. I was pretty lucky I only had that small incident.'
He said course familiarity was a factor in winning two of the three stage he won.
"The other was Eagle v Shark which is a track I hadn't ridden for about a year, so I was stoked with that."
McDowell said there are two ways to approach an enduro event.
"You can for it and go 100 per cent and throw a few crashes in, which always slows you down, or ride 85-90 per cent and try and have a clean day which is pretty much what I did and it paid off."
He wasn't sure how well he had done once he had signed out but once he started comparing times with other riders, he began to realise he was in with a shout.
Race organiser Neil Gellatly said getting the course ready for the event was tricky due to high winds and rain, and several fallen trees had to be cleared to allow the event to go ahead.
"I'm happy with the way it panned out. We had our challenges that we had to overcome and we overcame them and in the end it turned out really well - all those things you have to clean up post event, we hardly got any - most of the drama happened pre -event."
He plans to run the series again in 2017-18, but in a slightly more compact form with the first event later in October and the fourth round in April to try and avoid bad weather.
