In a standard tennis tiebreak, a player must reach at least seven points to win it, while also leading by two.
A tiebreak is normally played when a set reaches six games all. Unlike ordinary tennis games, its points are counted consecutively: 1, 2, 3 and so on. The first player to reach seven points wins if the margin is at least two points. Thus, a 7–5 finish ends the tiebreak, but a 7–6 score does not.
If the score reaches 6–6 in the tiebreak, play continues until someone establishes a two-point advantage. This means a tiebreak can finish 8–6, 10–8 or at an even higher score. There is no fixed maximum number of points.
The main source of confusion is that not every tiebreak uses seven points. A ten-point match tiebreak is common in deciding sets of doubles matches and is now used in Grand Slam singles final sets at 6–6. Those formats are different from the standard seven-point tiebreak.