A Magic match consists of a series of games that are played until one side has won a set number of games, usually two. Drawn games do not count toward this goal.
Most matches are usually won as 2-0 or 2-1. Matches that are 1-1-1 before the round ends should move onto a fourth game since neither side has won the set number of games. Two Headed Giant matches, unlike regular two player matches, are best of 1 matches.
If the round ends before a player has won the required number of games, the winner of the match is the player who has won the most games at that point.
If the round has ended and only one player has won a game then that player is the winner of that match because they have won the majority of games.
If both players have equal game wins, the match is a draw.
If the round has ended and the result is 1-1 or 1-1-1 then the match is a draw.
The Tournament Organizer may change the required number of games to be won for any portion of the tournament as long as this choice is announced before the tournament begins.
For example, the Pro Tour finals are played until one player wins three games. This is commonly known as “best of five,” though if games are drawn there can be more than 5 games. Note that this is typically not done outside of the Pro Tour or specially advertised events.
Match results, not individual game results, are reported to the DCI for inclusion in Planeswalker Points.
The results of the match are recorded for Planeswalker points. A win is worth 3 points, a draw is worth 1, and a loss is worth 0. Multipliers may factor in depending on the type of event. Casual tournaments you only receive participation points at, as match results are not reported. For more information check the information at the Planeswalker Points page.