“I think my serve wasn't so good tonight.”—Angelique Kerber, following her 6-4, 4-6, 6-2 win over Alla Kudryavtseva in Monterrey on Thursday, in which 18 of the 28 games featured service breaks.

I don’t know if the WTA keeps such stats—and I can see why the organization would want to downplay this particular category—but you have to wonder if this isn’t some sort of record. The break percentage was over 64 percent for the match, and you can’t even attribute this break-fest down to a clay surface. This Mexican event is on hard courts, where Kerber’s lefty serve and power game ought to shine—and vouchsafe service holds.

Kerber, the top seed in Monterrey, went on to take the lead in the Master of the Obvious award for April when she added, “I was broken a lot because I wasn’t serving very well, but then on the other hand I tried to focus more on my returns and on my return games, and so I broke her serve many times, too. Maybe that’s why we had a lot of breaks during tonight’s match.”

All kidding aside, it’s hard to explain away such poor service play (or is it such outstanding return play?). Granted, Kerber has been struggling, even though this early hard-court segment is favorable to her strengths. She started the year ranked No. 5, and while she’s slipped just one notch, she’s been beaten before the final in all seven of her events this year—often badly. WTA No. 27 Sorana Cirstea tagged her, 6-4, 6-0, last week in Miami, and she was routed in Doha by No. 32 Mona Barthel, 6-1, 6-2.

Kerber clearly is struggling, but is there a meta-narrative here? It seems like the return game in general is getting better and better across the board at a much faster clip than the service game of most players. It makes sense: The serve you bring to the table is a given, and you can’t improve your serve nearly as dramatically as you can your return. Dangerous returns used to be rare; everyone was focused on the conventional wisdom dictating that, first and foremost, you take care of your serve.

However, the slowing of court surfaces, changes in equipment (especially strings), and a heightened emphasis on the aggressive return—no doubt driven by the first two of those factors—are threatening to make a mockery of a foundation of the game: The assumption that you ought to be able to hold your serve, because initiating the point is so big an advantage. The entire scoring system is based on the idea that in order to win, you must find a way to break serve. That idea was diluted with the advent of the tiebreaker, but the “mini-break” is also the key to winning that set-ending overtime period.

The serve also seems somewhat devalued on the ATP tour—although the sheer power that some men bring to the shot has blunted this development. But did you notice that just last week, the Miami final between Andy Murray and David Ferrer produced a whopping 15 breaks of serve? And that Juan Martin del Potro’s semifinal win over Novak Djokovic at Indian Wells featured nine breaks?

The statistical sample here isn’t large enough to draw hard and fast conclusions, but it just could be that the age-old advantage of the server is being eroded, one pre-emptive return at a time.