Here are the candidates that I can muster from the top of my head. I can only go back to c1980. Please do remind me if I've missed someone:
*Highly controversial, as nobody else deserved the Australian Open of 2006 more than she did. But to be honest, I'd rather forget that tournament ever happened than include a slam amongst her tally during which she came past two of the elite players of the decade, who would both have been slim favourites to beat her, due to retirements. It wasn't Amelie's fault, but unfortunately she left that tournament unproven, in my opinion, and that result is null and void.
From that list, I think we can eliminate Myskina and Kuznetsova straight away. Both haven't won a great deal since (although Sveta won Miami last year), and hadn't been prolific tournament winners prior. Next, we can also get rid of Majoli. She had greater longevity than the aforementioned two, but her other feats were not outstanding when compared with the remaining players.
So we're left with:
This is where it gets more tricky.
Martinez, let's not forget, would have reached no.1 in the world in 1995 had the ranking system been calculated as it has been since 1996. During that season, she won six tier 2 or above titles. During her career, she also scored wins over all the great players of her heyday: Graf, Seles, Sanchez-Vicario, Novotna, Sabatini, Pierce, Navratilova, Hingis. And, of course, she has more career match wins -- far more! -- than any of the players in question, with around 730. Her nearest challenger in that respect is Sabatini with around one hundred fewer; only Evert, Navratilova, Graf, Wade and Sanchez-Vicario have won more. Martinez has greater longevity than any of the other players in terms of her span of wins over top ten players (1988-2005).
Jana Novotna was a Masters winner, Wimbledon champion and twice runner-up, defeating Graf, Seles, Sanchez-Vicario, Pierce, Sabatini, Navratilova, Hingis and Venus on more notable occasions than many of Martinez's victories. She also reached number two in the world, and after her Wimbledon triumph, was within only one hair's breadth of taking the number one spot in 1998.
Amelie Mauresmo has been a player capable of defeating any opponent for almost a decade now, ever since her run to the Berlin final as an 18 year-old in 1998. She has as many titles, or thereabouts, as Novotna, as well as wins over all of the top players of her day. She has won Wimbledon as well as the Masters, and numerous tier 1 victories.
However...I have written those eulogies in acknowledgement, because I believe the greatest competition is between Clijsters and Sabatini.
Clijsters vs Sabatini
- Sabatini, easily. Her first slam semi-final came in 1985, her last over a decade later in 1995 - and she retired at 26! Clijsters' first tier 2 or above victory was at the end of 2000, her last will be in 2007. Sabatini's last tier 2 tournament victory was in 1995 while her first, at a guess, would have been in 1986.
Career match wins -
Again, this is an area in which Sabatini wins easily. She won well over 600, while Kim is unlikely to reach above 450 by the end of the year.
- Clijsters wins handsomely, although a number of her titles have been below tier 2. Around 5 or 6 have been tier 3. Having said that, without checking the ITF database, some of Sabatini's earlier titles may also have been lower grade.
Major achievements outside the slams -
Unfortunately I don't have the stats, but (and a lot of people don't know this) Sabatini scored more wins over Graf during her career than any other player, including Seles. At one stage she really had Graf's number. Sabatini was also a four-time winner of the Italian Open, twice winner of the Masters and multiple Miami winner. Sabatini really was the player who could tear apart Graf and Seles' hegemony when she was playing her best tennis. In 1991, she defeated Graf and Seles in just one month (world no.'s 1&2), and had she won the French Open, would have been anointed world no.1.
Clijsters was very similar to Sabatini in that she was a thorn in the side to all of the great players, and one of the few who presented a real challenge to the Williams sisters during their brief stranglehold of the game. She was also twice a Masters winner, winner of Toronto, twice Indian Wells champion, Italian Open winner and Miami champion. And, of course, unlike Sabatini, she reached no.1 in the world, although it may be that Sabatini also would have achieved that feat in mid-1991 had the ranking system been then as it is now.
-- Clijsters can't be denied this one, although Sabatini was in far more slam semi-finals (something like 18!), compared to Clijsters' 12. However, the results that count are decisively in Kim's favour. She has won a slam and been 4 times a finalist, while Sabatini played just 3 slam finals, winning 1, during her entire career.
Wins over great players --
I'd say both are fairly even in this respect. Sabatini defeated Evert, Navratilova, Graf, Seles, Sanchez-Vicario, Novotna, Martinez, Capriati. Kim bested the likes of Hingis, Davenport, Venus, Serena, Capriati, Henin, Mauresmo, Sharapova.
I'll leave the conclusion to others