Novak Djokovic and Rafael Nadal are about to meet in one of tennis' most eagerly awaited Grand Slam quarter-finals. Here are four other memorable quarter-final contests.
2001 US Open: Pete Sampras v Andre Agassi
A classic, a five-setter in which Sampras prevailed, with neither man dropping serve. This was as big as big-name matchups get - they had won a combined 20 Grand Slams going into the contest. Sampras later commented that is was rare for two great players to meet with both playing great.
2006 French Open: Rafael Nadal v Novak Djokovic
The first meeting between the two which kicked off one of the greatest rivalries in tennis. Djokovic pulled out with a back injury in the third set but claimed he had discovered how to beat Nadal on clay where the Spaniard rules supreme. It took Djokovic another five years to do so.
2008 US Open: Serena Williams v Venus Williams
The sisters threw everything into the match, with Serena winning 7-6, 7-6 in a game of terrific rallies and power which thrilled the crowd. "I can't believe I won - wow," said Serena, the win giving her a 9 - 8 advantage over her older sister. Venus said: "I guess she played a little better."
2014 Australian Open: Roger Federer v Andy Murray
One of many memorable Grand Slam matches involving players from the modern day Big Four, with this meeting coming earlier than usual. Underdone since back surgery, Murray pushed Federer to four sets. A curio: Federer - Mr Perfect - struck controversy when he appeared to get away with a double bounce.
