Hi!
The list of global variables (general variables) are on page 177, section "9.4.7.1 General".
But the ones you need are tennis market variables, they are on page 191, section "Tennis Score Variables. Only valid in Tennis markets."
The player who was layed will have lay_matched > 0.
Also, you can get that selection by checking the condition:
Trigger {name of trigger that did the laying} Number of runs per selection is greater than 0
You can check the scores of each players in this way:
Trigger {name of trigger that did the laying} Number of runs per selection is greater than 0
AND
OR
Selection's Index is equal to 1
and Selection's Trigger Expression tennis_player1_games_won is greater than tennis_player2_games_won
OR
Selection's Index is equal to 2
and Selection's Trigger Expression tennis_player2_games_won is greater than tennis_player1_games_won
So you're saying, if my (layed) selection is the first in list, its number of games will be in tennis_player1_games_won, otherwise it will be in tennis_player2_games_won.
Use this logic to add more conditions or request a new trigger to add more requirements.