One of the biggest would be his service. At 196cm (6'5''), Bernard has quite excellent bodily parameters for a powerful service and also his service technique is, despite certain weakness in his legs and core, since years very solid. The below-presented photos are from the 2011 Masters Series tournament in..
Photos below show Casper's service during 2015 Orange Bowl. Even thought that his service was not that dominant back then, the most important basic characteristics of the Service 3.0 were already there at that time and provided a solid base for further development/improvement. The most important among them is the proper understanding of the "follow through 1" with a well-executed (well-pronounced) targeted pronation.
While Serena's service is being considered as the best in the game, service of her sister Venus is not much behind..., besides the technique also her tall body of 185 cm (6'1'') helps. The situation that Venus tends (mainly under stress) to tilt her head to the left side before the impact might be one of the reasons for her rather higher double fault rate than the one of Serena...
The above numbers tell us that Andy's service margins are mostly (besides aces) quite below the ones of his closest competitors. It's mainly his excellent return and rally game that make him to such a successful player he is. From the technical point of view, as I personally see it, a limited pronation and a rather unclear distinction between the follow through 1 and follow through 2 are the reasons behind Andy's lower service margins. Interestingly enough, Ivan Lendl (1st serve 56%, overall service points won 66%) had similar issues in his career.
As a tall player of 198 cm (6'6''), Delpo has quite some power potential, which he is using in all of his strokes. His body parameters and solid technique make also his service to a dangerous weapon, despite partly missing one distinct element common to the very best servers of the history. His career service statistics (until the end of 2016) are quite impressive - in the total of 5563 service games - 3272 aces (against 1100 double faults), 64% of the 1st services in and 74% winning percentage on the 1st service points.
Denis, who is being trained by his mother Klaudiya Istomina, possess quite solid and efficient stroke technique and his service fulfills all the requirements of the Service 3.0, which stands for service played with optimal body energy integration. Some details of his service can be seen on photos from the 2016 US.Open shown below:
Genie's service, in particular, didn't get so much attention yet, but despite some improvement possibilities concerning mainly the increase of its margin, it has a lot of good aspects, mainly around the body energy integration into the stroke. Genie mostly gains quite high percentages out of her serving points.
Here the distinction between her typical first service (usually more or less direct with just a slight topspin) and her famous kick service (heavy topspin with some sidespin used mostly as a second service) are quite visible. In both varieties, Samantha spends almost the entire stroke energy on the dominant (right, in her case as a right-handed player) side. The "follow through 1" (= the active part of the follow through) of the kick/topspin serve then goes, besides other differences to the first service, much more to the right.
Ivo Karlovic (*1979 / CRO) belongs to the most dominant servers/servicemen in the history of tennis and his more than 11,500 aces served throughout his professional career (as of December 2016) on the tour are a record hardly to be matched. At the height of 211 cm (6’11”) and weight of 104 kg (230 lb),...
From the point of the technique, Karolina has some excellent aspects of the Service 3.0 going most probably back to her early technical development stage in her junior years and also one little weakness leading to a lower margin at decisive (tense) moments like during her recent US.Open finals. Some of the main elements can be seen below..