I looked at the stats in AO after 2 rounds. We would think Nole will be the leader in return serve but NO! He was not in top 20 in first serve return points won and 20th in second serve return.
Service stats are winning percentage. On the other hand, return stats - a sum of pts won, so they are in favor of players who went through long matches. It's always puzzling me why they use two very different numbers. (ATP don't) It may be redundant over a single match, since serve/return % are mutually related. But over multiple opponents/matches, % is a far better indicator of which players are good in return games. Who cares if player A won more pts on return in a couple of five setters than player B did in two straightforward three setters. One can say aces/DFs lists also have the same issues to some extent.
38.4% (33/86) on return: 27.6% (16/58) on 1st, 60.7% (17/28) on 2nd
19.5% (15/77) on return: 16.3% (8/49) on 1st, 25.0% (7/28) on 2nd
51.1% (46/90) on return: 43.9% (25/57) on 1st, 63.7% (21/33) on 2nd
14.3% (8/56) on return: 14.7% (6/41) on 1st, 13.3% (2/15) on 2nd
But, he is 4th (84%) in first serve points won and 1st (79% ) in second serve.
Berankis is second in the second serve list with only 66%.
And Kohlscreiber's 91% is best in first serve points won while DelPo 2nd with 86%
Nole has better quality opponents in Mathieu and Harrison than Mannarino and Benji Becker for DelPo plus Starcis and Weintraub for Kohlscreiber.
I like it, even though it's based on small sample size.