I find such statements to be rather amusing (if ridiculous considering how inconsistent they are with the statistics).
First of all, when it comes to "stylistic differences" between players (i.e. opponents of different weight classes), the best measure of who played "better" isn't who hit more winners or less unforced errors. BTW, aces count as winners (Serena led 8-1), and double faults count as unforced errors (Halep led 3-2). The true measuring stick to determine who was "better" is
A) Figuring out the winners to errors ratio for each player. The player with the more positive differential is generally the one who played better (regardless of playing style).
B) Determining who had the higher "1st serve percentage". This in turn tells you who's serve was more reliable, and also which player had to depend on their groundstrokes more to win points.
C) Comparing the break points won percentage. This tells you who had more opportunities to break AND who played the bigger points better. In tennis, it isn't how many points you win, but WHICH points you win. In this match, Serena won both categories!
Williams:
First serve percentage = 47% (36 of 77)
Second serve points won = 63% (26 of 41)
Winners = 38
Unforced Errors = 45
Differential = -7
Break points won = 67% (2 of 3)
Total points won = 95
Halep:
First Serve Percentage = 72% (66 of 92)
Second serve points won = 58% (15 of 26)
Winners = 10
Unforced errors = 24
Differential -14
Break points won = 67% (4 of 6)
Total points won = 79
According to the stats, neither player played particularly great throughout the course of the match (although both had moments of brilliance, and some spectacular shots/rallies). Contrary to what many of the posters here seem to believe
Serena did not serve well in this match! (what the hell match were you guys watching?) However, she did play better from the baseline than Halep did (relying more on her second serve). And even though they both played the break points well, Serena had fewer opportunities to break throughout the match (the most important one being in the final set, giving her the win). Halep was in more of Serena's service games, than Serena was in Halep's (a stat which is backed up by the fact that Serena served at a lower percentage than Halep did). Serena won more points overall (based on her ground game) on her second serve, meaning that she was dictating play in the rallies. She also had a better winners to errors ratio!
That's how you determine who the better player was in the match!
Exactly!