# Women's Singles Tennis Match Analysis and Probability of Winning a Point
## 3 Results
### Further Statistical Information on Variables Influencing Performance  
Supporting Information Table S2 shows the points observed as a function of surface considering the following variables: service,rally length, bounce zone, finish zone, and point ending. In this study, the most observed combination of variables was first serve, shortrally, and final hit after a bounce in zone 1, accounting for 25%, 27%, and 27% of the total points played according to surface (clay, grass, and hard court, respectively). However, only 24%, 23%, and 18% of the points (depending on the surface) were won on the return in this combination. On serve, there were more winners on clay (20%) than on grass and hard court (17% and 16%). Winners targeting zone 1 (41%, 49%, and 33%) and zone 2 (24%, 27%, and 31%) predominated, although numerous zone 4 winners (24%, 14%, and 15%) were also observed. The majority of the points won by the serving player were due to forced errors by her opponent (52%, 58%, and 59%), mainly with shots from the baseline on clay (43%) and with shots into the net on the other two surfaces (48% and 47%). As for the return player, there were relatively few winners with the combination of variables mentioned above (8%, 9%, and 4%), with winners in zone 5 predominating on clay (38%) and in zone 1 on the other two surfaces (53% and 70%). Points won by unforced errors accounted for 13%, 21%, and 11%, with a clear tendency to miss with a shot to the net. Another of the most recurrent combinations recorded was first serve, shortrally, and final shot from zone 2, representing 15%, 11%, and 11% of the points depending on the surface (clay, grass, and hard court). The direction of winners hit by the serving player varied depending on the type of court. On clay, the winners went most often to zone 1 (29%) and zone 4 (32%); on grass, they went to zone 2 (32%) and zone 5 (28%); and on hard court, they went to zone 4 (30%) and zone 5 (37%). The percentage of points won on serve due to unforced errors by the opponent was lower than in the above combination (19%, 23%, and 18%). As for the points won with a return, this percentage was low (8%, 2%, and 3%), and they were obtained mainly due to unforced errors by the opponent (41%, 32%, and 39%). Among the other combinations, only one more, involving second serve, shortrally, and final hit after a bounce in zone 1, was recorded on more than 10% of occasions (13%, 13%, and 14% for clay, grass, and hard court, respectively). In this case, when analysing the data for the serving player, it was observed that she won 57%, 75%, and 68% of the points (76%, 79%, and 82% when the player started the point with her first serve). In addition, the percentage of points won by winners decreased (9%, 12%, and 10%) while the percentage of points won by forced errors increased as the surface became faster (47%, 56%, and 61%). If we focus on the player at the return, we can see that there was a higher percentage of winners on clay (20%) compared to the other two surfaces (10% and 15%), as well as points won by unforced errors (15%, 9%, and 11%). The other most frequent combinations detected were as follows: first serve, mediumrally, and final hit after bounce in zone 1 (5% on all surfaces); first serve, medium rally, and final hit after bounce in zone 2 (6% on all surfaces); and second serve, short rally, and final hit after bounce in zone 2 (7% on all surfaces). Supporting Information Table S3 shows an analysis of the points registered as a function of surface considering the following performance indicators: service, rally length, finish, and final stroke. On clay surfaces, there was a higher frequency of forehand winners in short and medium rallies, both with first and second serves, by the serving player. However, when there was a long rally, the percentage of forehand and backhand winners was similar. In contrast, the winners who were returning players tended to be more frequent with forehands in all possible combinations.