Serena Williams may have some competition in the fastest serve stakes if the speed gun results for this year's French Open are anything to go by.
WTA Staff

Clay court tennis is commonly associated with drawn-out baseline battles, but at Roland Garros the WTA's big servers were doing their best to keep these to a minimum.

Unsurprisingly, Serena Williams led the way in terms of both aces and service speed. Her fastest of the fortnight was clocked at 121.8mph - a figure matched by one of the game's stars in waiting, Naomi Osaka. They were not the only ones notching noteworthy numbers, either; Océane Dodin, Madison Keys and Danka Kovinic all threatening the 120mph mark.

Roland Garros
1T. Serena Williams - 121.8mph / 196.0kph
1T. Naomi Osaka - 121.8mph / 196.2kph
3. Océane Dodin - 119.9mph / 193.0kph
4T. Madison Keys - 119.3mph / 192.0kph
4T. Danka Kovinic - 119.3mph / 192.0kph

2016
1. Serena Williams - 127.0mph / 204.4kph (Indian Wells)
2T. Lucie Hradecka - 123.0mph / 197.9kph (Indian Wells)
2T. Venus Williams - 123.0mph / 197.9kph (Miami)
4. Timea Babos - 122.0mph / 196.3kph (Indian Wells)
5. Naomi Osaka - 121.8mph / 196.2kph (Roland Garros)
6. CoCo Vandeweghe - 121.mph / 194.7kph (Indian Wells)
7T. Madison Keys - 119.9mph / 193.0kph (Australian Open)
7T. Océane Dodin - 119.9mph / 193.0kph (Roland Garros)
7T. Polona Hercog - 119.9mph / 193.0kph (Australian Open)
10. Danka Kovinic - 119.3mph / 192.0kph (Roland Garros)

All-Time
1. Sabine Lisicki - 131.0mph / 210.8kph (2014 Stanford)
2. Venus Williams - 129.0mph / 207.6kph (2007 US Open)
3. Serena Williams - 128.6mph / 207.0kph (2013 Australian Open)
4. Julia Goerges - 126.1mph / 203.0kph (2012 French Open)
5. Brenda Schultz-McCarthy - 126.0mph / 202.7kph (2007 Indian Wells)
6. Nadiia Kichenok - 125.5mph / 202.0kph (2014 Australian Open)
7. Lucie Hradecka - 125.0mph / 201.2kph (2015 Wimbledon)
8. Anna-Lena Groenefeld - 125.0mph / 201.1kph (2009 Indian Wells)
9T. Ana Ivanovic - 124.9mph / 201.0kph (2007 French Open)
9T. Denisa Allertova - 124.9mph / 201.0kph (2015 Australian Open)