If you are a league follower, know the stats, who is in form etc, this not a gambling!
Gambling is when you play roulette and anything can happen.
In my opinion betting on sport is still gambling because there is always a risk of a player underperforming, injuring himself, or even a team underperforming as a whole. Maybe the other team just has a lucky day.
You don't know the odds when betting on sport. The sportsbooks determine it. So it is a gamble.