A 6–0 set does not need to reach deuce in every game to stretch beyond the theoretical 6–4 set with only 40 points. Here is a “Game Fish” depiction of game between Williams and Azarenka in Cincinnati in 2013:

Game Fish: Azarenka d. Williams (2013 Cincinnati). 12 deuces. 29 points.

With that game in a 6–0 set, only 11 more points (less than three games) need to be played to stretch beyond the theoretical minimum for a 6–4 set; that’s well below the 20 additional points that will be played.

The theoretical case I am defending is an eight point difference, but how realistic is it? Of the 4783 sets currently in the Match Charting Project (MCP) data, here is a graphic of the range of points played per set:

Depicts total points-per-set for 4783 sets. Click to be redirected to interactive version.

It is immediately obvious from the whiskers on the box plots that indeed the longest 6–0 set has more total points than the shortest 6–4 set. But let’s drill down a bit more and make a visual comparison between these sets…

(There is an interactive version of this chart at TennisVisuals.com, where it is possible to see the point distributions for specific players as well.)

Gasquet d. Duckworth (2014 Wimbledon)

Nadal d. Sousa (2014 Rio de Janiero)

The shortest 6–0 set in the MCP data is currently 28 points, for an average of approximately 4.7 points-per-game, while the longest is 55 points (9.5 ppg).

The shortest 6–4 set in the MCP data is currently 45 points, for an average of approximately 4.5 points-per-game, while the longest is 98 points (9.8 ppg).