When we read books, we find some fictional characters somehow assume traits of people whom we know and talk about.
Although the fictional world of magic created by J.K. Rowling doesn't have many such resemblances to actual persons [excepting her friends], I have observed that certain quidditch players do share some characteristics with certain tennis stars.
Some of the qualities is seen in more than one player, but the highlighted features are only those which resemble fact and fiction very very closely.
1. Ron Weasley/ Marat Safin: Ron is my favourite character in the books. Try as I did to find some similarity between Ron and Federer, my favourite tennis player, I failed miserably; but found out that Ron's sporting acumen was more on the likes of Marat Safin.
Both are erratic, suffer from acute sense of nerves while playing, and when they get going...no one can stop them! They just need the right dose of motivation from the right channels and that's it!
2. Harry Potter/ Roger Federer: Harry is supposed to be the best seeker the school has ever seen. He is nimble, quick, alert, light build: "in fact the right build for a seeker" as the authoress puts it.
Roger in many ways displays harry like qualities on the court; he is nimble, light on his feet, accurate on his shots. The similarity between Harry on his broomstick and Roger with his footwork on the court is just one of its kind.
3. Cedric Diggory/ Andy Roddick: Cedric always played his game with absolute sportsmanship which has been seen more than once in Roddick. Both believe in playing with sincerity and fairness as much as they can.
4. Oliver Wood/ Novak Djokovic: Oliver is the captain of Harry's quidditch team and has this habit of egging his team on till they cry out frustrated and tell him to stop. Djokovic, on the court, constantly eggs himself on between shots which reminds me uncannily of Wood.
Another thing similar about Wood and Djokovic is that both of them are ruthless when it comes to their game. Winning at that point, for them, becomes the only thing and not everything!
5. Viktor Krum/ Rafael Nadal: Krum is the most prolific player who plays for the Bulgarian quiddditch team. He is stubborn and aggressive when it comes to his game and is a maverick in his own right. Rafa demonstrates these qualities to the hilt; although there is one thing that they both differ as players: Krum loves attention from everyone, whereas Rafa is very shy off the court.
6. Weasley Twins/ The Bryan Brothers: The Weasley twins are the prodigal beaters in the sport, and the Bryan Brothers are a prodigy as a doubles team. The coordination and the level of play of both the pairs of twins is like hitting the bulls eye!
7. Ginny Weasley/ Dinara Safina: Ginny has carved a name for herself among the names of her quidditch playing brothers. Dinara, though, doesn't have that many brothers as Ginny has proved herself when compared with her brother Marat. Extraordinary players, the two with absolute all-round capabilities in their respective sports.
P.S There are many more quidditch players mentioned in the books but most of them in passing or specifically in one or two books, so I have not considered them.