Three Grand Slams. Six Masters 1000 titles (a record). 11 tournament wins. The year-end title at the ATP World Tour Finals. An 82-6 record. A lead over the No. 2 player by a staggering 7,915 points, the equivalent of almost four Grand Slam titles. More than $21 million in earnings, a new ATP record. Altogether, Novak Djokovic put together a staggering season of tennis that’s clearly one of the best in history. But is it the all-time best? To answer that question, we had to open up the history books (or, to be more literal, open up the browser) to look at the question from all angles, Hawkeye-style. Here’s how our quest for the answer unfolded:

1. Eight men have won three Slams in a single season since the start of the Open era.

Djokovic instantly gets put on the list because of his three Slams, something that’s been done be only a few men in modern history. It’s a list populated by tennis greats: Connors, Wilander, Nadal, Federer (x3) and Djokovic himself, who also pulled the feat in 2011, his other entry in the “best year ever” race.

2. Djokovic is sixth in terms of all-time single-season winning percentage.

It is from this list we’ll choose the all-time greatest season. That’s why Djokovic’s other great season — his 2011 that started with a 41-match winning streak — isn’t here. (He finished 70-6. There are those who would defend that season as his best — that win streak was unbelievable. But Djokovic was exhausted by the end, dumping the WTF in November, losing to Janko Tipsarevic and David Ferrer and failing to get out of the group stage, which is a big X.)

1. John McEnroe — 1984 — 82-3 (.965)

2. Jimmy Connors — 1974 — 93-4 (.959)

3. Roger Federer — 2005 — 81-4 (.953)

4. Roger Federer — 2006 — 92-5 (.948)

5. Bjorn Borg — 1979 — 84-6 (.933)

6. Novak Djokovic — 2015 — 82-6 (.932)

3. Djokovic faced the most top-10 players in his season than anyone else did in theirs.

First, this is where we (quickly) leave 1978 Bjorn Borg. Maybe he was more dominant than McEnroe in ’84 or Federer in ’05 or anyone, but the numbers can’t support that contention. He had so many wins against inferior players and didn’t win all three Slams, which is sort of a prerequisite for this debate. McEnroe is also gone despite leading the win-percentage list. He didn’t play the Australian Open that year and though he won 14 titles, two Grand Slams doesn’t get you entry on the greatest-season register. (Not that McEnroe in ’84 wasn’t playing tennis at one of the best clips in history. He was 22-1 against top 10 players which, as you’ll see, is better than anyone else.) Here are the records against top 10 players by our remaining candidates in their special seasons:

Federer ’05 — 15-2 (.882)

Djokovic ’15 — 31-5 (.861)

Fed ’06 — 19-4 (.826)

Connors ’74 — 6-2 (.750)

Djokoic’s 2015 is first on this lis on sheer volume alone. He had just one loss to a player outside the top 10, the same as Federer in 2006. This is where we bid adieu to Connors. Tennis was a different game back then, more of a barnstorming sport. And again, like Borg and McEnroe, he might have been playing better than anyone else in that year, but without competition against the best in his sport, it’s hard to validate.

4. Analyzing the losses

Here are the combined ranks of the players who defeated the players in their contending seasons.

Federer (’05) — No. 30.5 (the bad loss was to then-No. 101 Richard Gasquet, hardly a horrible defeat)

Federer (’06) — No. 5.8 (he lost four times to No. 2 Rafael Nadal — thrice on clay — and to Andy Murray when the Muzzard was No. 21)

Djokovic — No. 7.8 (his worst loss was at the start of the season to the big-serving Ivo Karlovic)

Federer in 2006 wins here. He lost four times to the second-best player in the world entering his prime and to a player who was about to enter his. The Djokovic loss to Karlovic, while meaningless, hurts him in the category, even if overall has no bearing on the rest of the season.

5. Analyzing the wins

Federer ’05 — 11 titles, three Grand Slams, 4 Masters wins, four other wins

Federer ’06 — 12 titles, three Grand Slams, 5 Master wins (including ATP WTF), four other wins

Djokovic — 11 titles, three Grand Slams, 7 Masters 1000 events (including ATP WTF) and a lowly 500 event in Beijing.

Some differences to cloud the picture even more: In 2005 and 2006, the Masters schedule was different and many of the finals were best three-of-five, theoretically a bonus for The Fed. So there is no winner here, though we’d lean Djokovic if we had to. Winning six Masters 1000s is insane. So if it’s a wash, let’s go deeper into competition:

Federer was 27-3 against top-20 competition in 2005.

Federer was 30-4 against top-20 competition in 2006.

Djokovic was 38-5 against top-20 competition in 2015.

That’s basically a tie too. They each played tough competition at the same percentage, with Djokovic having a few more matches against better players. He also played the fewest matches against players ranked No. 100 or below (six, less than Federer’s 10 in 2006 and 16 in 2005, one of which he lost — though it was the aforementioned Richard Gasquet match).

As for quality of finals opponent:

Three of Federer’s 11 titles in 2005 came against the No. 2 or 3 player in the world, with another coming over Andre Agassi.

Two of Federer’s 12 titles in 2006 came against the No. 2 or 3 player in the world.

Seven of Djokovic’s 11 titles in 2015 came against the No. 2 or 3 player in the world (Federer or Murray).

Advantage: Djokovic. It’s so hard to compare different eras, which is especially odd given that 2006 and 2015 should be the same eras, but are different in terms of season construction. Given the Masters requirements now, Djokovic is inherently going to play a better field. Even though Federer in ’05 and ’06 had little control over that, is still a check-mark for the Djoker.

But you can’t control who you play and we’re not going to try and analyze the quality of opponent or the field on a quanitative level — is Lleyton Hewitt in 2005 better than Stan Wawrinka in 2015? That’s a whole other argument no one wants to have.

6. How many sets did they lose at a Grand Slam?

Federer ’05 — 9 sets lost

Federer ’06 — 13 sets lost

Djokovic ’15 — 14 sets lost

That’s one for team Federer ’05, even though I’m of the thought that it really doesn’t matter how many games or sets you lose, as you long as you win.

7. How many finals did they make?

Federer ’05 — 12 of 15 tournaments

Federer ’06 — 16 of 17 tournaments

Djokovic ’15 — 15 of 16 tournaments

It’s here we part with you, 2005 Roger Federer. If the goal is to put yourself in a spot to win tourneys, the 2006 Fed and 2015 Nole did it better. Bouncing a a guy with an 81-4 record. You can tell we’re in the big leagues now.

8. Intangibles

a. Federer finished 2006 on a 29-match winning streak. Djokovic didn’t lose from mid-August to mid-November (both losses to Federer) and finished the year on a 26-1 run.

b. Playing 97 matches (as Fed did in 2006) is a 10% increase over the 88 matches Djokovic played. That’s not a massive number but it’s sizable. Federer also played two more tournaments and won one more.

c. Djokovic made a record $21,646,145 in earnings this year.

d. Federer was 25 years old for most of his 2006 season. Djokovic turned 28 just before the French Open.

e. In the final rankings of 2006, there were a total of two Grand Slam champions in addition to Federer — Nadal and Andy Roddick — though Lleyton Hewitt, Andre Agassi and Gaston Gaudio were in the top 10 at various points during that season. This year, there are four Slam winner in the top 10 besides Djokovic.

f. Record by surface for both players:

This is where it gets interesting. All of this info we’ve discussed before, but it’s jarring when you see it in print. Up until now, everything had pointed toward this Djokovic season ranking as the best ever. But these numbers raise eyebrows. Federer was nearly unbeatable on hard courts and grass in 2006, winning 97% of his matches. Djokovic was just about as good, winning at a 93% clip. Djokovic gets Federer on clay, however. But there’s a caveat: Federer’s three losses on the surface were all to the greatest clay-court player in history, the aforementioned Mr. Nadal. (Federer was 2-4 to the 20-year-old Rafa in 2006, with three of the losses on clay. Djokovic was 5-3 against a 34-year-old Federer in 2015.)

Let’s get to the crux of the discussion: Both Federer and Djokovic were 27-1 in majors during their respective years, winning three tournaments and dropping the final of the other (both lost the French final in four sets, coincidentally).

Djokovic’s loss was to a former Slam champion in Stan Wawrinka, but one who sort of got lucky in winning his first title (Nadal got hurt during the match, which takes nothing away from Stan — staying healthy is as important as anything — but it’s an important note). Federer’s defeat was against an unstoppable force, a 19-year-old who turned 20 during the tournament and was winning his second of nine French Opens(so far). He has 14 Slams in all, tied for second of all-time.

Federer lost to an all-time great on clay three times (during a year when he finished a perfect 26-0 on the surface — the best single-season clay-court record of his career), while Djokovic lost his sole Grand Slam match to a player who had nine career titles at the time and just one in a clay tournament above the 250 level. What happened in that match? Long story short, Djokovic basically choked it away (or “got tight” if “choke” is too incendiary). He was better than Stan that week but couldn’t get it done when it mattered most. It was his chance to join Serena Williams and get halfway to a Grand Slam. It was his chance to become the fifth man of the Open era to win a career Slam. And he blew it. It’s forgotten because of all his other greatness in 2015, but this was the undisciplined Djokovic, who used to make appearances earlier in his career, coming back to haunt him.

When you get past all the numbers, winning percentages, quality of opponents and other things, the Grand Slams are clearly what matter most. So while Djokovic had a slight edge over Federer in non-Slams, Federer gets him in the majors. He lost to the greatest clay courter the tennis world has ever seen (after winning the first set 6-1, by the way) while Djokovic lost to a fine player in a match he should have dominated. Though I spent every moment researching and writing this post assuming the final conclusion would be that Novak Djokovic’s 2015 was better than all, recalling that Wawrinka match changes it. In what was his most important match of the year, Djokovic basically crumbled after winning the first set.

9. Which player had the greatest season in tennis history?

Roger Federer in 2006, by a net cord over Novak Djokovic and his still-amazing 2015 campaign.