Daily Data Viz: Why has Serena been unable to reach 22 Slam titles?

World No. 1 Serena Williams has failed in her last three attempts to capture her 22nd career Grand Slam singles title—what stats are the difference-makers in these matches?

World No. 1 Serena Williams has failed in her last three attempts to capture her 22nd career Grand Slam singles title. Her loss to Roberta Vinci at the 2015 U.S. Open and her loss to Angelique Kerber at the 2016 Australian Open could be attributed to Serena just making too many mistakes, failing to capitalize on her opportunities or issues with her most important weapon, her overpowering 1st serve.

In her 2015 U.S. Open semifinal loss, Serena made 40 total unforced errors and converted just one of her six break points in the two sets she lost. 22 of her 40 unforced errors came from her backhand side where she can struggle when her footwork gets a bit sloppy—two handed backhands require more precise footwork.          

In her 2016 Australian Open final loss, Serena made 46 unforced errors and put just 53% of her 1st serves in play (49% in play in the two sets she lost). In the set she won, Serena made a total of five unforced errors in 52 points played (one for every 10 points played). In the two sets she lost, she made 41 unforced errors in 124 points (one for every three points played).

But her loss to Garbine Muguruza in the 2016 Roland Garros final was somewhat of a different story. Usually Serena is the dominant player, the aggressor who sets the tone and determines the outcome. But this match differed from her other most recent Grand Slam defeats in that Serena was outhit and was the player on the defensive for the majority of the match. Muguruza actually had more unforced errors than Williams (25 to 22), but she won 57 points by hitting winners or forcing an error from Serena. Williams won just 44 points in that manner.

One of the big reasons that Muguruza was able to be so dominant was Williams hit just 49% of her first serves in play for the match, similar to her performance in Australia. This allowed Muguruza to be very aggressive on return of serve and she took advantage by winning 20 of 35 points when Serena had to hit a 2nd serve.

Coming into Wimbledon Serena Williams leads the WTA Tour in service games won and is 2nd in 1st serve points won but has won less than half of her 2nd serve points. As good as she is, Serena is at a disadvantage when she has to hit a 2nd serve and that is amplified when she’s facing her toughest opponents.  So keep an eye on her 1st serve percentage and her unforced errors—when those go the wrong way even the best in the world will struggle.

Check SI.com's Wimbledon 2016 Daily Data Viz hub page throughout the whole tournament for the latest data-driven infographics and charts from IBM, the official technology partner for Wimbledon. IBM captures and analyzes the data that powers all of the Grand Slams, as well as the digital platforms that extend the experience to fans around the world.