Big serves and power tennis. That's what the grass season is all about. With the tour's Premier grass events around the corner, SAP and WTA Insider preview the turf.
WTA Insider Courtney Nguyen
June 15, 2018

SAP Inside the Numbers is an ongoing series which looks to preview and reflect on the tour's major swings throughout the season.

With the biggest grass-court events just around the corner in next week's Nature Valley Classic (Birmingham), the Mallorca Open, and Nature Valley International (Eastbourne), all culminating in the third Slam of the season at Wimbledon, SAP and WTA Insider dig deeper into the numbers to highlight what to expect over the upcoming weeks on the green turf. 

Here's how the 2017 grass court season played out last year:

The Spaniard is the first woman from her country to win Wimbledon since 1994. (©Getty Images)
Garbiñe Muguruza became the 1st Spanish woman to win Wimbledon since Conchita Martinez in 1994. (Getty Images)

Wimbledon: Garbiñe Muguruza d. Venus Williams, 7-5, 6-0. 

Karolina Pliskova with her Eastbourne trophy after beating Caroline Wozniacki 6-4, 6-4 in the final (Getty)
Karolina Pliskova is still looking to make it past the 3rd round of Wimbledon for the 1st time.

Eastbourne: Karolina Pliskova d. Caroline Wozniacki, 6-4, 6-4.
Birmingham: Petra Kvitova d. Ashleigh Barty, 4–6, 6–3, 6–2.

Anett Kontaveit won her first title in Den Bosch (Getty)
Now inside the Top 30, Estonia's Anett Kontaveit won her 1st title last year in s'Hertogenbosch.

Mallorca: Anastasija Sevastova d. Julia Goerges, 6-4, 3-6, 6-3.
s'Hertogenbosch: Anett Kontaveit d. Natalia Vikhlyhantseva, 6-2, 6-3. 
Nottingham: Donna Vekic d. Johanna Konta, 2-6, 7-6(3), 7-5. 

The WTA grass season is a short one. With just three weeks of tournaments after the French Open, it can be a tight scramble to gain matches and confidence ahead of Wimbledon. Some players prefer to keep their preparation on the practice court. Serena and Venus Williams, who account for 12 of the last 18 Wimbledon titles, have rarely played tournaments before The Championships. Serena has played a tour-event just twice, in Eastbourne in 1998 and 2011. Venus has played three times, also in Eastbourne, in 1997, 1998, and 2011. 

Wimbledon Champions (active players)

Serena Williams: 7 (2002, 2003, 2009, 2010, 2012, 2015, 2016)
Venus Williams: 5 (2000, 2001, 2005, 2007, 2008)
Petra Kvitova: 2 (2011, 2014)
Maria Sharapova: 1 (2004)
Garbiñe Muguruza: 1 (2017)

But for a vast majority of the tour, transitioning from a slow, high-bouncing surface like clay to the quicker, low-bouncing grass requires match-play, which means the upcoming events in Birmingham, Mallorca, and Eastbourne regularly feature top-level entry fields. Given the unpredictable nature of grass and the elite fields, it is no surprise that the grass bounty has been spread fairly evenly amongst the tour's best grass-court players.

Among active players, only 4 women have won multiple WTA grass-court titles: 

Madison Keys: 2014 Eastbourne, 2016 Birmingham
Karolina Pliskova: 2016 Nottingham, 2017 Eastbourne
Maria Sharapova: 2004 Birmingham, 2005 Birmingham
CoCo Vandeweghe: 2014 s'Hertogenbosch, 2016 s'Hertogenbosch

Keys is the only woman to have 2 Premier grass titles to her name. Despite their grass-court bona fides, only Sharapova has progressed past the quarterfinals at Wimbledon. Pliskova has yet to progress past the third round at Wimbledon, Keys was a 2015 quarterfinalist, and Vandeweghe is a two-time quarterfinalist in 2015 and 2017.

The numbers don't lie: the serve is the shot to watch on grass. Comparing the tour's serve and return numbers across surfaces last year shows the marked improvement in service holds and breakpoint saves when the tour turns to grass. This puts the tour's best returners like Simona Halep and Angelique Kerber, both of whom feature in the Top 10 of the WTA Insider Grass Court power Rankings, under incredible pressure, but both have proven their ability to succeed on grass. Kerber was a Wimbledon finalist in 2016, while Halep was a semifinalist in 2014. 

In 2017, the tour average for return games won on grass was just over 30%. This season, Halep goes into the grass season winning over half of her return games, 50.2%, this year, while Kerber is just below her at 46.2%. All eyes will be on how quickly they can dial in their return games on grass this year. 

With the serve set to be the biggest weapon during the grass season, here's a look at where the 2018 WTA Ace Leaderboard stands. Julia Goerges, a finalist in Mallorca last season, continues to rack up the aces, while a trio of Czechs sit right behind her in Karolina Pliskova, Kristyna Pliskova, and two-time Wimbledon champion Petra Kvitova. 

The Czechs may hold a lock on the cumulative ace tally, but when it comes speed the Americans win out. A trio of Americans top the 2018 serve-speed list so far, with Madison Keys, Venus Williams, and 19-year-old newcomer Caroline Dolehide locked in a three-way tie for the fastest serve of the season.