Seven-point and ten-point tie-breaks
Understand the two-point margin, service rhythm and difference between a set tie-break and a match tie-break.
Seven is a threshold, not a cap
In the standard tie-break described by the ITF, points are counted zero, one, two and onward. A side must reach seven with a two-point lead to win the game and set. A 7-6 score is not enough.
If the margin remains one, play continues. The tie-break can finish 8-6, 10-8 or later. The winning threshold and margin are separate conditions.
Serving follows a different rhythm
The side whose turn it is to serve takes the opening point. The other side serves the next two. After that, service alternates in blocks of two points, with the doubles rotation maintained where applicable.
This explains why the serve marker moves after the first point and then after pairs. Keep the current server separate from the side leading the score. A service change does not necessarily signal an error.
Ten points can mean different phases
The ITF permits alternative formats involving ten-point tie-breaks. A match tie-break can replace a deciding set. A final-set ten-point tie-break at six games all comes after a deciding set has reached 6-6. Those are different places in the match.
Both use the specified two-point margin, but a match tie-break is not a set containing ten ordinary games. A 6-5 tie-break score can have very different stakes depending on whether seven or ten is the threshold. Read ScoreZaap's phase and completed set scores, then check the event conditions if the format is unclear.