If one talks about brothers and sisters in the sport of 90+ square-inch rackets and the 50+ gram fluorescent yellow balls, one would quickly think of the Bryan Brothers and the Williams' sisters of the current generation.
While Bryan brothers carved a niche in doubles game, which is of lesser interest to many, the diametrically opposite characters of Williams' sisters had stamped their own authority in the ladies Singles as well as the doubles game.
Williams' sisters, Venus and Serena, had begun their assault on Grand Slams a decade ago and have amassed a total of 18 Grand Slam singles titles with their brute force and highly powerful ground strokes which were unseen before in womens tennis.
In addition to these, they also won 8 Grand Slam doubles titles and two Olympic Gold doubles medals in 2000 and 2008.
In an out and out whites-dominated game, they have written their place in history books in black with staggering records in all areas of the game.
Two of the fiercest competitors, as the sisters in their own right, their initial clashes in Grand Slam finals used to be exciting. Venus with huge serve and bludgeoning ground strokes to Serena's aggressive all round game. A bout of true two lady heavy weight champions before the glam dolls from Eastern Europe made their foray into the womens game.
As they started winning the slams on a consistent basis dominating tennis with their power game, people started losing track of their individual GS count. A part of the reason could be their tight strangle hold on the Slams in Singles or Doubles which lead to a monotony in the final result or a part of it could be due to the feeling that "Whoever wins, they are sisters anyway".
With both living at the same residence, at times it becomes difficult to imagine them competing at a fierce level in all of the Grand Slam finals they contested. After their initial assault on the trophies was satiated, it may get to a stage where the match could well have been fixed in the sisters mind before the first point was played.
They can make the game as much ultra competitive as they would love to with a winner emerging from nowhere like in a WWF match.
When the opponents are not siblings, they have the luxury to not attempt few points when they are tired after a long service game. Even if they haven't given 100% percent in one of the games one would always expect them to fight with renewed determination in their next game.
If the opponent is hitting the lines with his services then the returner need not even bother to raise his racquet--a feature often displayed in Ivo Karlovic's matches.
Being the siblings on court, one cannot have that leeway to relax and they are forced to give their 110 percent to break the public perception of "sisters anyway".
A couple of points here and there should make the difference between the winner and the loser in such a physically demanding game.
Tennis is such a game where even a tad lame execution of a backhand can cause the ball to run into the net or a slight deviation from the normal forehand swing can help the ball land into the tramlines without causing any doubt in the spectators mind.
No matter with whatever trophy cabinet of the duo would be studded with trophies, medals and records there could probably be few points played in favour of the other sister which would have appeared normal to the spectator.
If one of the siblings were treated shabbily by their parents in their childhood, or if one is a half brother or a half sister who has not received his share of love and affection in their growing up days, it can then ignite the fire under one to prove her point over the other at a big stage constantly.
Otherwise, it takes a ruthless person to slog it out at the highest level in all the finals to go one up over the opponent giving no chance to his brother or sister all the times.
It is very difficult to find a sibling pair, in tennis at least, who have been doing exceedingly well in singles as well doubles game for over a decade.
But, for all the intensity and passion they bring on to the courts, at one point or the other in a match, there could be a point where a blood-relation and affection can get into the bigger scheme of things in deciding the winner, which may not be outright conspicuous to a tennis fan.