With the help of SAP analytics, wtatennis.com contributor Craig O'Shannessy takes a look back at an absorbing Miami Open.
WTA Staff

MIAMI, FL, USA - There is a lot you can't see in a tennis match.

The ball flies around quickly, often times looking more like pinball than patterns being constructed. That's where numbers come in, speaking a unique language that helps uncover the real strategies and percentages that dominate our evolving game.

SAP compiled detailed analytics from 50 matches at the Miami Open, creating a valuable snapshot into what is exactly happening in the women's game at the moment. These kind of numbers help create a framework for fans, players and coaches to understand and develop our wonderful sport.

Serving
The average first serve speed was a very respectable 96mph, and 81mph for second serves (Serena Williams averaged 106mph/84mph). Those numbers are trending upwards, with players getting fitter, stronger and developing more efficient serve motions. Overall, 54% of points were won on serve, with 61% on first serve, and 44% on second serves.

In the deuce court, 41% were directed out wide, 20% at the body, and 39% down the middle. Those numbers can improve, as there should be more serves (around 50%) directed out wide to open up a hole for the ensuing groundstroke. The middle target down the T is a smaller target to hit, and also drags the returner into the middle of the court where they immediately neutralize the angles. Nobody knows this better than Serena, who directed 57% of her first serves out wide in the deuce court.

The reality of tennis is that most serves are returned, and at Miami 75% of first serves were returned, and 86% of second serves came back in play - for a combined total of 79%. That's why the wide serve needs more attention, as it offers the best angles, is a high-percentage target to hit, and instantly creates more holes. The more you think of the serve, and the first shot after the serve, as a "Serve + 1" unit, the better.

More opportunity for improvement exists in the ad court, with 46% of first serves being directed down the middle, 22% at the body and only 31% out wide. The wide ad serve is a golden opportunity to stretch the opponent hitting a backhand, returning the ball to a favorable crosscourt location, and immediately opening a hole behind to wrong foot.

Break Points
Servers averaged saving 49% of their break points for the tournament, including 57% on first serve, but only 37% on second serves. Andrea Petkovic excelled in this key area in her great run to the semifinals, winning 67% of break points she faced, including 70% of first serves and an extremely high 60% on second serves. She served no aces, but also, more importantly, no double faults on these key points, making serves deep to the backhand in the deuce court and more to the body/forehand in the ad court.

Returning
The return of serve is a weapon in it's own right, and players were a lot more aggressive against second serves as you would expect. The average return speed against a first serve was 63mph, but that elevated to 71mph when returning second serves. Forehands were the preferred weapon, averaging 68mph to 64mph on the backhand side.

What's very encouraging to see is the aggressive court position players were making contact from. Overall, 32% of first serve returns were hit inside the baseline, and 70% of second serves were inside.

Rallying
Depth is a key factor once the point develops, and 81% of all groundstrokes landed past the service line in Miami. In the 50 recorded matches, there were 1456 winners hit, and the old school of thought that the women's game is more dominated by the backhand is truly dead and buried.

Almost double (961 to 495) of all groundstroke winners were from the forehand wing. The forehand receives more good news, considering that it is basically twice as potent as the backhand, but unforced errors are very even with 1279 from the forehand and 1110 from the backhand side. Carla Suárez Navarro relied heavily on her forehand in her great run to the final, hitting 53 forehand winners and 17 from the backhand side. Overall, she directed 62% of her groundstrokes through the ad court.

Once a point is constructed, it's very clear that players are trying to match up the strength of their forehand against their opponent's comparatively weaker backhand side. Of the shots hit deep of the service line, 54% were directed through the ad court and 46% through the deuce court. The area that got the most attention was the outer half of the ad court, directed wide to the backhand, with 28% of all groundstrokes landing in this high-traffic area. Simona Halep was slightly higher than the average at 30% to this critical landing area.

Court Position
Where you stand matters, and players are definitely improving their court position relative to the baseline. Overall, 27% of shots were contacted standing inside the baseline, and 72% behind. Those are healthy numbers that show a determination to attack with the feet as well as the hands. Serena is once again the runaway leader in this area, hitting an amazing 46% of her shots inside the baseline. Overall for the tournament, 85% of all groundstrokes shots were topspin, 13% backspin, and 2% flat.

The average rally forehand speed was 69mph - once again slightly better performing than the backhand at 67mph. The average rally length for the tournament was 6.5 shots, which shows the determination to employ a lot more first strike tennis than in years past.

These key SAP metrics help us understand the game on a deeper, yet clearer level than ever before. The analytics revolution in tennis has clearly arrived, and the tennis world can learn a lot from what just happened in Miami.

Craig O'Shannessy (@BrainGameTennis) is the leading analyst for wtatennis.com throughout the 2015 season, utilizing SAP Data & Insights to uncover the patterns and percentages that dominate the game. Visit Craig's website at www.braingametennis.com for more expert strategy analysis.

SAP