After all those Grand Slam finals between Roger Federer and Rafael Nadal, a record eight in all, there's a new tantalizing tennis rivalry.
This one, between Nadal and Novak Djokovic, offers the added benefit of being more competitive.
And given the participants' ages, it should last awhile.
Nadal and Djokovic played each other to decide the titles at each of the past four Grand Slam tournaments, most recently the French Open, where Nadal won a two-day, rain-interrupted final 6-4, 6-3, 2-6, 7-5.
No one should be surprised if they make that five in a row in less than a month at Wimbledon.
Which would be remarkable, considering that before these two came along, no pair of men had met in more than two consecutive major finals since the start of the Open era in 1968. Not Borg and McEnroe. Not Sampras and Agassi. Not even Federer and Nadal.
"We are very young, and we played over 30 times against each other," said Djokovic, who trails 19-14 overall in their series, "and hopefully we can have many more battles in the next years."
The No. 1-ranked Djokovic turned 25 last month; No. 2 Nadal is barely a week past his 26th birthday.
They've already accumulated more head-to-head meetings than Nadal and the 30-year-old Federer (Nadal leads 18-10), and are gaining in the Grand Slam final department (Nadal leads Federer 6-2; Djokovic leads Nadal 3-2).
If they do meet again at Wimbledon next month or the U.S. Open in September, there will be those who will wonder whether Nadal's current three-match winning streak against Djokovic — at Monte Carlo, Rome and Paris, all on red clay — says much about who has the upper hand in general at the moment.
It might just reflect superiority on one particular surface.
"I don't think (Nadal) necessarily still has the answers. I think he fights through this match, and it's clay, and he's confident, and he wins the key points there toward the end," seven-time major champion Mats Wilander said after presenting Nadal with the trophy at Roland Garros on Monday.
Right now, there's such a tiny sliver separating Djokovic and Nadal.
They're probably the sport's two best returners of serve, two best movers and two best retrievers of opponents' shots. They're also capable of switching from defense to offense in a blink as well or better than anyone. In the French Open final, they played more than 60 points that lasted 10 strokes or more — long, complicated exchanges that resulted not from conservative, keep-the-ball-in-play tennis, but rather an extraordinary ability to force the other to come up with the goods over and over — and each won more than 30.
Wilander pointed to the puzzle of the top three men in the sport, Djokovic, Nadal and the No. 3-ranked Federer, a trio that has combined to win 28 of the past 29 Grand Slam titles dating to 2005. (The exception: Juan Martin del Potro beat Federer in the 2009 U.S. Open final.)
Nadal always seems to have the edge over Federer. Until recently, Federer had the edge over Djokovic, who beat the Swiss star in the U.S. Open semifinals in September and the French Open semifinals last week. And for a stretch of seven consecutive wins that began in 2011 and was capped by the 2012 Australian Open final — a 5-hour, 53-minute epic — Djokovic had the edge over Nadal.
"If you're going to build a player that's going to trouble Roger Federer on every surface, you build Nadal. And if you're going to build a player that's going to trouble Nadal, you build Robin Soderling with the movement of Novak Djokovic. And suddenly, Novak Djokovic at No. 1 is hitting the ball like Soderling, but he moves like Novak," Wilander said. "So it's amazing how they all fit each other really badly. The one big thing is Novak has now maybe turned the corner on Federer completely after here. ... He's the one to beat (at Wimbledon) — Novak is still the one to beat, for sure."
Djokovic had won 27 consecutive Grand Slam matches until his setback against Nadal in Paris, falling one win short of becoming the first man since Rod Laver in 1969 to win four straight major titles. Nadal, beaten by Djokovic in London, New York and Melbourne, avoided becoming the first man to lose four straight major finals.
"For us, it was very important to win here against Djokovic, because a fourth Grand Slam loss would have been ugly," said Toni Nadal, Rafael's uncle and coach.
Now they start over at Wimbledon, where play begins June 25. Before opening the defense of his first title at the All England Club, Djokovic will rest — he's taking this week off.
Nadal isn't wasting any time getting ready to move from clay to grass courts, flying Tuesday to Germany, where he's entered in a tournament on the green turf. His schedule provides no downtime: travel Tuesday morning, practice on grass Tuesday afternoon, doubles match Wednesday, singles match Thursday.
"That's the calendar," he said. "The calendar says we only have this period of time on clay, and I don't have more chances to play on clay."
Don't feel too sorry for him. Sure, Nadal is the undisputed King of Clay, owner of a record seven French Open titles. But he also already owns two Wimbledon championships, in addition to three runner-up finishes there — against Federer in 2006 and 2007, and against Djokovic last year.
Nadal already owns 11 Grand Slam titles, Djokovic five. Put those numbers together, and you get Federer's 16, the record.
The question isn't whether Nadal and Djokovic will continue to add to their totals.
The question is how many more times they will do it at the other's expense.
Howard Fendrich covers tennis for The Associated Press. He can be reached at hfendrich(at)ap.org or http://twitter.com/HowardFendrich