In my opinion, a tier system works much better overall, compared to trying to single out any one player as the greatest ever. I think that you have arguably 4-5 guys in this very top tier. I've long held the view that Laver, Borg, Sampras, and Federer are in the top tier, but a very strong argument can also be made for Pancho Gonzalez to be up there. You can make arguments both for and against any of them, so you'll have difference in opinion. I do think Rafael Nadal will also eventually end up in that "top tier" of greatest players.
What does one value the most in terms of criterion? How is one's own personal experience with tennis a factor in that person's subjectivity? This is necessarily both a subjective and objective exercise, no matter how you slice and dissect it from every vantage point. Anytime you have different eras, different conditions, different equipment, different surfaces, different competition, and so forth, you can never have truly direct comparisons, so you are necessarily left with subjective assessments to consider. For example, Borg played with a very heavy frame 16 ounces plus with weighting (double ply wood due to high tension), 80+ pounds tension, and no modern strings. Think of Borg playing with modern frames and poly strings, and even new shoes, given his game and the playing surfaces of today which have all arguably tilted the balance in favor of baseliners away from serve and volleyers/net rushers. I think he would be so tough to handle.
Consider the following in the case of Bjorn Borg:
-Bjorn Borg was dangerous on any surface. He could also serve and volley quite adeptly when required. At 20, in 1976, he served and volleyed very frequently to take that title without losing a set
. I don't know of another player in the Open Era that has won Wimbledon without the loss of a set. He won titles on hard courts, clay courts, grass courts, and indoor courts. If one thinks he was predominantly a "clay courter", they'd be overlooking his ~23 or so indoor titles, 5 straight titles on the fast grass of Wimbledon and his 41 match win streak there, and also ~6 or so hard court titles. His worst H2H record with a rival that I know of is 7-7 versus McEnroe (and that was only on hard courts, grass, and indoors, with no clay court matches). The only two players he lost to in the finals of majors were Connors and McEnroe. He played against very tough competition, with guys like Ashe, Connors, Nastase at or near the top early in his career, and later, players such as Vilas, Gerulaitis, Connors, McEnroe, and Lendl as foes at the majors. This was during times when there was much more variety in surfaces and court speeds. He won the 1978 French Open having lost 32 games (the lowest total for a major won I believe, at least in the Open Era).
- When the "Iceman" was playing at the top, the 4th biggest tournament of the year was either the WCT finals (esp. in the 70's) or the Masters (as it was in Jan. 80 and Jan. 81). He won the last two Masters that he played on indoor carpet in New York, going 5-0 vs. Lendl, Connors, and McEnroe. He won 6 FO titles. He reached 6 straight W finals, and won 5 in a row. The big hole in his resume was the US Open, but dig deeper there. He played in exactly 4 hard court majors during his career (the US Open). He reached the final on 3 of 4 of those occasions.
-Bjorn Rune Borg has the best winning percentage of any player in the Open Era at the "majors" (nearly 90%). Before one dismisses that, due to his early departure from tennis, note that neither Federer or Nadal could match that % through the age of 25 (nearly 26). He is also at the very top of all players in overall winning percentage at nearly 82%.
-He has been SO influential as a tennis player, impacting all pro players that followed. Bob Kain, his former agent and former IMG CEO, once said that "all players today should thank Bjorn for their big paychecks", because he "really took tennis endorsements to the next level". He was the first player to gain million dollar endorsements.
-He played at the top for a long time. He also won at least 1 major for 8 straight years. Look at his total match totals, even though he stopped playing full time at a relatively young age. Plus, back then, the top players like Connors and Borg played heavy "unofficial" schedules, playing at big money exos, that were often quite competitive and important for players. That was on top of a heavy playing schedule, without all the insulation provided to the players of today (from media, fans, etc.). Borg was a rock star like no other in tennis, so he would regularly be mobbed at hotels and basically wherever he went. He had to rely heavily on his coach Lennart Bergelin to help him with that. Borg was the first player to have a full time coach that traveled exclusively with him everywhere and to all tournaments. Now, that is standard practice.
-Consider the fights that he and Connors had with Tour Officials through the years. In 1982, officials at both Wimbledon and the French Open decided to force Borg to play in the qualifying rounds if he decided to reduce his official playing schedule during that year. There had been a recent split between the WCT and the ATP at that time and the Tour was in disarray after enjoying a dizzying climb up in terms of popularity and commercial success after the Open Era. The rise in the profile of tennis in that it came out of the country clubs and out into public parks did not happen overnight. That happened largely on the backs of players like Connors, Evert, Ashe, Borg, McEnroe, Navratilova, and Laver/Rosewall/Gonzalez, etc. before them. So how did Tour officials reward Borg for his very significant role in the raised profile of tennis? Remember he was playing Davis Cup by 16, he won Junior Wimbledon, etc. Borg wanted to drop down his official schedule, take time off, and really only focus on the majors during 1982 at least, but he met much resistance. That played a huge role in his decision to leave and experience life outside tennis. Later, I think he regretted making that decision, though I think he had every right to basically say "later" to the Tour, but in hindsight, I think he realized that perhaps he should have stuck around and basically played just enough to qualify directly into the main draws of majors, but hindsight of course can be 20/20.
I don't think any other player has influenced modern tennis as much as Borg did. Not Sampras, not Agassi, not Lendl, not Connors, and not even the great Rod Laver. His athleticism, sportsmanship/modesty, style of play, and ability to gain international attention playing tennis, all played a part in his becoming an all time great tennis player. Borg was truly a tennis revolutionary, that really didn't let how others viewed him change the opinion he had of himself (per Bob Kain). He didn't need constant praise and adulation from fans and others to remind him that he was a great tennis player. He KNEW he was great and no one could tell him different.
How many players used a two handed backhand and a great deal of topspin off both wings during his time? Who learned to somehow dominate even at Wimbledon playing a great deal of baseline tennis? Borg had great reliance on baseline play at Wimbledon, but he also had the ability to win lots of point at the net and with big serving. He proved all the naysayers wrong who said confidently that his "style of play" would never triumph at Wimbledon.In the 1970's-early 1980's, who was hitting a FH like this with a wood frame, where the reduced width provides for significantly
less margin of error given Borg's swing path?
As to any all time great tennis player, you can point to deficiencies or weaknesses, but one really needs to look at the full picture. In my book, Borg is "Number One", largely due to his tremendous
impact on the modern game. If Bjorn Borg never played tennis, I firmly believe that tennis would look and feel quite differently than it does today.