Every tennis record comes with an asterisk.
What we’re mainly interested in are achievements at the top level of the men’s or women’s game. I often use the term “tour-level” as shorthand for this, kind of like saying “Major Leagues” for baseball to cover the American League, National League, and a handful of long-ago defunct organizations. It disguises unnecessary complexity and allows to get to the point.
For men’s tennis, “tour-level” generally means all ATP events, plus grand slams, plus Davis Cup. Excluded are challengers, futures, and qualifying at all levels. Usually we limit consideration to the professional era, though if we’re talking only about Slams, there’s no artificial start date.
Which Davis Cup matches? Grigor Dimitrov is 16-9 this year, but two of those wins were in Davis Cup Group 2 against Finns outside of the top 900. Should we exclude Group 2? (The ATP does.) How about Group 1? (The ATP doesn’t.) How about any rubber when the opponent is outside the top 200?
And therein lies a major problem, and one that is not limited to records and streaks. The level of a tennis match is not defined by the ranking points on offer; its difficulty is determined by the quality of the opponent. In the middle of Robin Haase’s 15-month streak of lost tour-level tiebreaks, the Dutchman did win a breaker, in Rome qualifying against 81st-ranked Sergiy Stakhovsky. It doesn’t “count.” But a main-draw match one month later against 640th-ranked Mate Pavic does.
There’s no good solution. It isn’t a matter of tennis’s “analytics problem,” it is a reflection of the structure of the sport.