With Roger Federer and Rafael Nadal set to meet in the semi-finals at Indian Wells, we chart the rivalry and remember some memorable encounters.
Nadal leads the head-to-head with Federer 23-15 but the Swiss has won the past five encounters.
They have not met since Shanghai in 2017, the same year that Federer crushed his great rival in the fourth round at Indian Wells.
Here, we look back at some of their most memorable meetings.......
Miami Masters final, 2005
In only their second meeting, Federer came from two sets down on hard court to beat an 18-year-old Nadal. Federer even trailed 5-3 in the third-set tie-break but came roaring back to seal the title and deliver a statement victory. Nadal would go on to win his first French Open two months later.
Federer won 2-6 6-7 (4-7) 7-6 (7-5) 6-3 6-1
Rome Masters final, 2006
Nadal had won his previous 52 matches on the red sand and was odds-on favourite. Federer, however, pushed him close in the Eternal City, squandering a fifth-set break and two match points in a pulsating encounter. Federer had won all of the three previous Grand Slams but Nadal, ranked world No 2, had established himself as the Swiss' chief rival.
Nadal won 6-7 (0-7) 7-6 (7-5) 6-4 2-6 7-6 (7-5)
Wimbledon, 2007
In a repeat of the 2006 final, a never-say-die Nadal pushed four-time champion Federer to five sets for the first time in his 34-match winning streak at the All England Club. Federer, who had never lost a match at Wimbledon after winning the first set, was in his absolute pomp, and claimed the crucial first-set tie-break despite Nadal's gallant efforts.
But Nadal's blistering passes and serve-and-volley kept him in the match. It was a close contest until Federer claimed a decisive break in the sixth game of the fifth set and had to wipe away the tears as he celebrated equalling Bjorn Borg's five Wimbledon triumphs.
Federer won 7-6 (9-7) 4-6 7-6 (7-3) 2-6 6-2
Wimbledon final, 2008
Federer was looking to clinch his 13th career Grand Slam title and sixth straight Wimbledon trophy in one of the most eagerly-anticipated matches of their long rivalry, but Nadal had just thrashed Federer for the loss of just four games in the French Open final and he would beat the Swiss in his own citadel at Wimbledon.
Nadal stormed into a two-set lead but Federer surged back, salvaging a fourth-set tie-break, including staving off two championship points, to earn a fifth. A rain delay added to the drama but when they returned it was Nadal that prevailed, breaking at 7-7 before securing his first Wimbledon title. The contest is widely considered to have been the greatest the sport has ever seen.
Nadal won 6-4 6-4 6-7 (5-7) 6-7(8-10) 9-7
Australian Open final, 2009
Federer was bidding to win his 14th Grand Slam and equal Sampras' all-time record but Nadal was now No 1 and in with a chance to become Spain's first Australian Open champion. Nadal looked in trouble when his opponent breezed through the fourth set but he found another level in the fifth and Federer was powerless to respond.
Nadal became the first man since Goran Ivanisevic in 2001 to win a Grand Slam with five-set victories in the semi-finals and final. An emotional Federer found defeat hard to take, prompting an iconic photograph of Nadal consoling his rival during the trophy ceremony. It remains Nadal's one and only Australian Open title.
Nadal won 7-5 3-6 7-6 (7-3) 3-6 6-2
French Open, 2011
This was Nadal and Federer's eighth and last meeting in a Grand Slam final and having ended Novak Djokovic's 41-match unbeaten run in the semi-finals, the Swiss was hoping his form would be enough to dethrone Nadal.
Nadal reeled off five straight games to take the opener and then capitalised on his momentum and kept his composure in the tie-break to take a commanding two-set lead. A resilient Federer delighted the crowd in a tough third set as he clawed his way back into the match, but he squandered break-point opportunities on Nadal's opening serve in the fourth and from there the tide swiftly turned.
Nadal won 7-5 7-6 (7-3) 5-7 6-1
Australian Open, 2017
Federer won a record 18th Grand Slam title in a thrilling five-set final.
The 35-year-old won a classic encounter to become the oldest major-winner in 45 years and move four titles clear of Nadal and Pete Sampras on the all-time list.
For Federer, it sealed an astonishing comeback from six months out with injury. His fifth Australian title came seven years after his last.
Federer won 6-4 3-6 6-1 3-6 6-3
Miami Masters & Indian Wells, 2017
Federer continued his mastery of Nadal in a re-run of the Australian Open final when he outclassed and overpowered his great rival in Miami.
Federer won 6-3 6-4
They met again just weeks later in the desert and it was Federer again who produced a breathtaking performance to dismantle Nadal with casual assurance.
Federer won 6-2 6-3
Shanghai, 2017
Federer maintained his dominance over Nadal with an imperious 72-minute display to secure his sixth title of the year.
The Swiss now has the advantage on hard courts (11-9).
Federer won 6-4 6-3
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