Harry Potter was a very talented Quidditch player so he caught in snitch in most matches he played. The only book that doesn't feature Quidditch is the fourth and seventh book.
In the Quidditch match, Slytherin is ahead by 200 points. So Harry being the Seeker, must only catch the Snitch when Gryffindor is ahead by 80 points or more, because if Harry catches the Snitch, the game ends, and they get 150 points, which would put them below Slytherin for the Quidditch Cup.
A professional Quidditch match does not end, under any circumstances, until the snitch has been caught. The WINNER of the match, however, IS decided by a point system. Whichever team has the highest score after the snitch has been caught is the winning team.
A quaffle, two bludgers, and one Golden Snitch
4 balls are used, if you count the snitch. There is one Quaffle, two bludgers, and the golden snitch.
Each goal is worth ten points.
150 points
There are 4 different balls used in Quidditch: -The Quaffle : Used for scoring, Is a bright scarlet colour, Is the biggest ball. -The Bludgers: There are two of them, used by beaters to knock people of brooms. -The Snitch: This is a small golden ball, Caught by the Seeker to end the game and earn 150 points.
Harry Potter played many games during his time at Hogwarts. In one of his most notable games against Hufflepuff, he caught the snitch in only five minutes.
16 points
Quidditch is the most popular sport in the wizarding world, where there are three hoops on the pitch's either end, seven broom-riding players per team (3 Chasers, 2 Beaters, 1 Keeper, and 1 Seeker), and four balls (1 Quaffle, 2 Bludgers, and 1 Snitch). To get points, the Chasers work together to throw the basketball-like leather Quaffle into the hoops guarded by the other team's Chaser. Each hoop is worth 10 points for their team. Meanwhile, the heavy black Bludgers try to unseat as many players as possible, while a team's Beaters attempt to redirect the Bludgers toward their opponent's members with heavy bats. Almost separate from the action is the Seeker, who tries to hunt down and catch the quick, tiny winged Golden Snitch. A game does not end until the Snitch has been caught, and the Seeker who catches the Snitch earns 150 points for his respective team.
If you are talking about the first book/movie, then they were actually losing, because while everyone's attention was focused on harry falling off his broom, a slitheran was making shots and no one was stopping him.