It's almost impossible to imagine tennis without Venus and Serena Williams. The two sisters began their professional careers in 1994 and 1995, respectively, winning many majors and profoundly impacting the sport.
But as the saying goes, all good things must come to an end.
Serena announced in August via a first-person essay on Vogue.com that her playing career is winding down. She didn't use the word "retirement," instead opting for "evolution" when describing her eventual exit from professional tennis. She said her desire to grow her family was a reason for walking away and suggested the 2022 US Open could be her final tournament.
Venus, however, hasn't revealed much about her tennis future. After losing to Belgium's Alison Van Uytvanck in the first round of the US Open, Venus said in a postmatch news conference that she was "just focused on the doubles," which she played with Serena.
On Thursday, the Williams sisters lost their first-round doubles match against the Czech Republic's Linda Noskova and Lucie Hradecka 7-6, 6-4. It was the first doubles night session at Arthur Ashe Stadium since Mike and Bob Bryan defeated Colin Fleming and Jonathan Marray in the men's doubles quarterfinals in 2013 and the first women's doubles night session there since the Williams sisters lost to Nadia Petrova and Maria Kirilenko in the third round in 2012. Thursday's match was possibly the last time we will see Serena and Venus take the court as doubles teammates.
Serena was eliminated by Ajla Tomljanovic in the singles third round on Friday. No matter where their careers take them next, the Williams sisters' legacies as tennis legends are ironclad. And we have the stats to prove it.
Here are some numbers behind Venus' and Serena's Hall of Fame-worthy careers:
The Williams sisters
14: Venus and Serena have won 14 women's doubles Grand Slams as partners. The only duo with more in the Open Era is the pairing of Pam Shriver and Martina Navratilova (20).
3: The Williams sisters have won three Olympic gold medals as doubles teammates (Sydney 2000, Beijing 2008, London 2012).
2002: After the 2002 French Open, where Serena defeated Venus 7-5, 6-3, the sisters ranked Nos. 1 and 2 in the WTA rankings. It was the first time in WTA history that sisters occupied the top two spots. Serena ended the year as No. 1 and Venus No. 2.
136,930,533: As of Thursday, The Williams sisters have earned a combined $136,930,533 in prize money in their careers. Serena has received $94,618,080 and Venus $42,312,453.
31: Serena and Venus have faced each other 31 times in singles matches. Serena holds the advantage with a 19-12 record. Nine of those games have occurred in a Grand Slam final. Serena again has the edge with a 7-2 record.
23: Serena has won 23 Grand Slam singles championships. That's the most by any player in the Open Era (since 1968) and is second-most all time. Margaret Court is first with 24.
367 and 73: Serena has won 367 major matches, the most by a woman in tennis history. She has also won 73 career singles titles, the fifth-most among women in the Open Era.
4: Winning all four Grand Slam events in tennis is not an easy task, let alone consecutively. But Serena has proved otherwise. She has won four straight majors twice in her career (2002-03 and 2014-15). Steffi Graf is the only other tennis player to achieve that feat.
Four is also the number of Olympic medals Serena has won, all gold. She earned her hardware in doubles at the 2000 Games, singles and doubles at the 2008 Games and doubles at the 2012 Games.
30: Serena's dominance after 30 years old is a testament to her longevity and skill. These are some notable feats Williams has achieved since she turned 30:
She has won 10 Grand Slams, seven more than any other woman in the Open Era.
Williams won the 2017 Australian Open at 35 years, 124 days old, becoming the oldest woman to win a title in the Open Era. She didn't drop a set throughout the event and played while pregnant with her daughter, Olympia. After her Australian Open win in 2017, Serena was ranked No. 1 in the WTA rankings, becoming the oldest person to hold the top spot.
319: How dominant is Serena? She spent 319 weeks as the ATP or WTA's No. 1-ranked player during her career. To put this into perspective, only four other players have spent 300-plus weeks as the ATP or WTA No. 1 player (Graf, Navratilova, Novak Djokovic and Roger Federer).
186: Serena spent 186 consecutive weeks as the WTA's No. 1 player from February 2013 to September 2016. That's tied for the longest streak at No.1 since WTA rankings were introduced (1975).
91: With a wild-card entry into this year's US Open, Venus has appeared in 91 major singles events. That's the most by any player in the Open Era.
7: Venus is a seven-time Grand Slam singles champion, trailing her sister for most among active players. It's also tied for eighth-most among women tennis players in the Open Era.
Feb. 25, 2002: On this date, Venus reached No. 1 in the WTA rankings and spent 11 weeks there. She became the first Black man or woman to hold the No.1 spot since ATP (1973) and WTA (1975) rankings began.
1: Opponents shouldn't doubt Venus, even if she is a double-digit seed. She is the only woman in the Open Era to win multiple Grand Slam singles titles as a double-digit seed. Venus won Wimbledon in 2005 as a No. 14 seed and in 2007 as a No. 23 seed.
5: Wimbledon has treated Venus well. She has won the tournament five times, fourth-most among women in the Open Era. She trails Navratilova (9), Serena (7) and Graf (7).
Also, Venus is a five-time Olympic medalist. She won gold in singles and doubles at the 2000 Games, doubles at the 2008 Games and doubles at the 2012 Games. Venus also won silver in mixed doubles at the 2016 Games. Her five medals are tied with Kathleen McKane Godfree for most by a tennis athlete.
ESPN Stats & Information contributed to this story.