Widely regarded as the premier head-to-head rivalry in individual sports, clashes between tennis' leading men invariably turn into spectacular wars of attrition and a showcase for the brilliance of both players.
However, the rivalry, while one of the game's best assets, is in danger of losing its sheen if Federer cannot find a way to keep pace with his Spanish foe.
Nadal leads their matches 13-6 and has won each of the past five, including three Grand Slam finals: at the French Open, Wimbledon and this year's Australian Open.
Last weekend's final of the BNP Paribas Open at Indian Wells was supposed to signal the resumption of hostilities between the pair, as Federer returned to the tour following a lengthy break after his defeat in Australia.
That reunion, though, was disrupted by Andy Murray, the precocious young Scot who has now beaten Federer four straight times and is looking to make his own push for the top.
Federer still has far too much game for anyone else in the world except for Nadal and Murray, and reports of his demise are woefully premature. He remains one of the finest players the world has ever seen, but this period of his career is an opportunity to showcase his true mettle.
If Federer can find a way to conquer the mental demons which seem to grip him every time he is forced to up his tempo against Nadal or Murray, it would be one of the most notable achievements in a glittering career that has produced 13 Grand Slam titles.
And more importantly, for tennis, it would rescue a magnificent rivalry from turning into a one-way ticket to predictability.
Nikolay Davydenko has spent four years in the top 10 of the ATP rankings, but that could soon come to an end. The consistent Russian is unable to defend his 2008 Miami victory because of a foot infection. He is likely to drop to at least No. 9, with Fernando Verdasco and Gael Monfils also capable of overhauling him with good performances at Key Biscayne.
USE YOUR FREQUENT-FLYER MILES
The Sony Ericsson Open becomes the focal point of both tours for the next two weeks. Last year's event saw upsets aplenty on the men's side, with Andy Roddick snapping an 11-match losing streak to Roger Federer, Novak Djokovic losing to qualifier Kevin Anderson and Nikolay Davydenko topping Rafael Nadal in the final. Another poor showing by Djokovic here would put him in danger of losing his No. 3 ranking to in-form Andy Murray.
Vera Zvonareva was on fire in the desert last week as she stormed to victory in singles and doubles (with Victoria Azarenka) at the BNP Paribas Open. Zvonareva is one of the hottest players on tour this year and is now a genuine contender in the closely fought battle for dominance at the top of the women's game.
LAST WEEK'S WINNERS
BNP Paribas Open, Indian Wells: Rafael Nadal
BNP Paribas Open, Indian Wells: Vera Zvonareva
THIS WEEK'S PREDICTIONS
The Miami tournament doesn't end until April 5, but the Monday Slice likes its chances of continuing our winning streak. Mr. Nadal retains our faith after entering the winner's circle for us last weekend, while Serena Williams must be a strong favorite as she returns from a minibreak thanks to her boycott of Indian Wells.
Sony Ericsson Open, Miami: Rafael Nadal
Sony Ericsson Open, Miami: Serena Williams