Top 10 Highest Earning Tennis Siblings of All Time

It's believed that the tennis term "love", which refers to a score of zero, is adapted from the phrase "for the love of the game" or "to play for nothing". However, in professional tennis today, players are definitely playing for something. At the 2014 Australian Open alone, the total prize money was more than $29 million, an increase of more than $3.5 million from the previous year's sum.

The term "love" is still appropriate in tennis to some extent, though. Sibling love, in particular. Over the years, several sets of siblings have made their mark in the game, many of them playing together and sometimes against each other. These sibling partnerships and rivalries have made for some of the most compelling tennis storylines sports fans have ever witnessed.

Here's a look at the most financially successful siblings to have ever graced the sport of tennis, their career winnings adjusted for inflation:

10 Manuela, Katerina, and Magdalena Maleeva / Combined Prize Money: $14.3 Million

Yulia Berberyan was Bulgaria's finest tennis player in the 1960s, so it wasn't all that surprising when all three of her daughters took up tennis as they were growing up. What was amazing, however, was how successful they all became in the sport. All three sisters, at different points, made it to the top 24 in the world in doubles and the top 6 in the world in singles. Of the three, though, it's Manuela, the eldest, who reached the highest ranks: #11 in doubles and #3 in singles. Altogether, they won 39 singles titles and 11 doubles titles, Katerina reaching the finals of the 1994 US Open Women's Doubles competition. The three sisters also have the distinction of each beating one of the all-time greats, Martina Navratilova.

Today, the family owns and manages the Maleeva Tennis Club in Sofia, Bulgaria.

9 Agnieszka and Ursula Radwanska / Combined Prize Money: $16.7 Million

These sisters may be from Poland, but they're definitely not "poles apart". In fact, Agnieszka and Ursula seem to echo each other's affection when they're asked about their off-court relationship. Ursula says, "We are best friends, we are so close. We have always been together -- participating, living and traveling together -- so it is nice to have my sister on tour." Meanwhile, big sister Agnieszka reveals, "We share things, we go shopping and we have a good time, so sometimes when I am traveling alone without her, I feel so lonely."

Being around each other often seems to be good for the sisters' performance. Ursula, currently ranked in the mid-40s, has made it to as high as #29 in the world. Agnieszka, meanwhile, is currently in the top 5 after peaking at #2. She's also a three-time WTA Fan Favorite Singles Player (2011, 2012, 2013), has won thirteen singles titles in her career, and played in the 2012 final of Wimbledon.

8 Byron, Wayne, and Cara Black / Combined Prize Money: $17.8 Million

The Black siblings from Zimbabwe aren't usually mentioned as being among the royal families of tennis, but they deserve to be. Byron is a former #1-ranked doubles player, Wayne is a two-time men's doubles Grand Slam champion, and Cara is a three-time women's doubles Grand Slam champion who has been ranked the #1 women's doubles player in the world. In fact, Cara has won the mixed doubles titles in each of the Grand Slam tournaments, giving her a career Grand Slam in mixed doubles.

Byron and Wayne have already retired from the tour, but Cara is still on the tour despite being close to 35 years old. In fact, she's still the 14th-ranked women's doubles player in the world.

7 Bob and Mike Bryan / Combined Prize Money: $26.2 Million

Currently the most popular set of twins in tennis, Bob and Mike Bryan of the United States are considered by many to be the best men's doubles team ever. Together, they have collected multiple Olympic medals, including the gold in 2012, and have won more professional games, matches, tournaments and Grand Slam titles than anyone else in tennis history. The Bryans have also finished the ATP year-end rankings at #1 for eight years. In fact, they've achieved a non-calendar year Golden Grand Slam by holding all four major titles and the Olympic gold medal simultaneously.

Interestingly, in their early days as junior players, they were forbidden by their parents to play each other in tournaments. Whenever they were scheduled to face one another in tournaments, they alternated defaults.

6 Marat Safin and Dinara Safina / Combined Prize Money: $29.8 Million

The haters of either Marat Safin or Dinara Safina are likely to point to the other sibling as proof that being mentally weak runs in the family. And these non-believers would have some evidence to back their claim. Marat had many emotional outbursts and displays of fiery temper in his career, which seemed to hinder his ability to gather more than the two Grand Slam titles he won (2005 Australian Open, 2000 US Open). Dinara, meanwhile, was never able to win a Grand Slam title despite reaching three finals (2009 Australian Open, 2008 and 2009 French Open). She also failed to win the women's final of the 2008 Olympic tennis event. Nevertheless, Russia's Marat Safin and Dinara Safina have nothing to be ashamed of as they've secured their place in history by being the first and still the only brother-sister tandem in tennis history to achieve the #1 ranking.

While Marat formally retired on November 11, 2009, it's still uncertain whether Dinara will come back to play. She left the tour in 2011 due to a back injury, and Marat has said that his little sister is done. However, Safina has clarified that she has yet to make a final decision on her retirement.

5 John and Patrick McEnroe / Combined Prize Money: $33.8 Million

It's not very easy to be in the same line of work as a big brother who seems to be significantly better at it. That was the case for Patrick McEnroe, whose older brother, John, is a much more accomplished tennis player than he is. Patrick also had a successful tennis career, however. While he only won one singles title as a professional, he claimed sixteen doubles titles, one of them being the 1989 Tour Finals and the 1989 French Open. John, meanwhile, is considered among the all-time greats, having won three Wimbledon titles (1981, 1983, 1984) and four US Open championships (1979, 1980, 1981, 1984). He also became the world's #1 singles player in March of 1980 and the world's #1 doubles player in January of 1983.

Today, while the brothers occasionally butt heads on the direction of youth tennis in the United States, they both serve as tennis commentators and play doubles as a team in legends matches.

4 Andy and Jamie Murray / Combined Prize Money: $33.9 Million

In the 2014 Australian Open, Andy couldn't fully concentrate on his second round match because earlier in the day, his older brother Jamie had collapsed with heatstroke after his first round doubles match victory. Andy was still able to escape his match with a win, but he later admitted, "What was happening with Jamie is more important than my match."

It's heartwarming to know that Andy has managed to keep his tennis career in perspective despite all his success. His first big victory came in the 2012 Olympic Games, where he won the gold medal match against Switzerland's Roger Federer. He then went on to win his first grand slam title, the 2012 US Open. Nearly a year later, Andy became the first British man in 77 years to win Wimbledon.

Jamie, meanwhile, is a doubles specialist who has won ten doubles titles in his career, two of them, with younger brother Andy.

3 Javier Sánchez, Marisa Sanchez, Arantxa Sánchez-Vicario, and Emilio Sánchez / Combined Prize Money: $40.9 Million

When the Sanchez siblings were playing tennis on the men's and women's tours, aside from being known as winners, they were also known as an inseparable family. The children traveled with their parents as the Sanchezes achieved varying levels of success. Arantxa, the most accomplished, became #1 in the world and won multiple grand slam titles. Emilio reached #7 in the world and was captain of the Spanish Davis Cup team. Javier reached the top thirty, while Maria found some success at the US university championships.

Unfortunately, in 2012, Arantxa revealed, "The myth of a united and happy Sanchez Vicario family was just that: a myth." In fact, she has accused her parents of leaving her bankrupt and causing her to owe huge sums to the Spanish finance ministry despite career earnings that amounted to $58 million. She has also revealed that she maintains no relations with her siblings.

Arantxa's parents have denied her claims.

2 Novak, Marko, and Djordje Djokovic / Combined Prize Money: $63.2 Million

It's not very easy to play tennis on a professional level while always being associated with an older brother as accomplished as six-time grand slam winner and former world #1 Novak Djokovic. That's something Marko, 22, and Djorde, 18, are realizing.

The brothers have received direct entry into several tournaments trying to raise their profiles by having a Djokovic play in their events. However, as a result, Marko and Djorde have often had to do battle against players far too skilled for them to beat. Worse, Marko struggled with injuries throughout most of 2011, and even after he had regained his health, his match wins came in trickles. Djordie, meanwhile, has managed only two wins in his first full season on the professional circuit. The younger brothers refuse to give up though, and Novak recognizes that they're still young and still have a chance to attain success on the men's tour.

The world #2 says, almost too kindly, "I'm really happy to see my brothers, especially the younger one, doing well now in tennis. Because it's not easy for them. They're still not mature enough to be able to face these really difficult mental struggles all the time.... They're carrying the burden of the Djokovic family.... They understand that they have to fight their own way through and hopefully they will."

1 Serena and Venus Williams / Combined Prize Money: $102.7 Million

It's almost impossible to use superlatives when describing the achievements of sisters Venus and Serena Williams. Venus is the first American black woman to become World #1 during the Open Era. She has also won seven Grand Slam singles titles, more than any other active female player but one. That one player is younger sister Serena, currently World #1 (the oldest in history) and winner of seventeen Grand Slam singles trophies. In fact, she is the most recent player, male or female, to have held all four Grand Slam singles titles simultaneously. As a pair, the sisters have also won 13 grand slam women's doubles titles and three Olympic gold medals.

However, it's very clear to Venus and Serena that their relationship is more important than their tennis careers. Serena sums it up perfectly: "Tennis is just a game; family is forever."

More in Tennis