Nadal looks for renewed vigour against Nishikori
Although Nadal has dubbed the 13th seed a "fantastic player", the Japanese has lost all of his four matches against the claycourt machine.
Paris: Seven-times champion Rafael Nadal has been showing signs of nerves at the French Open, but Monday's fourth-round match against Kei Nishikori could be exactly what the doctor ordered for the Spanish third seed.
Although Nadal, who will celebrate his 27th birthday on Monday, has dubbed the 13th seed a "fantastic player", the Japanese has lost all of his four matches against the claycourt machine.
Nishikori is also a novice of the second week at Roland Garros, having previously never gone past the second round in Paris.
"Now comes the moment when I need to change the dynamic," said Nadal. "I have my opportunity on Monday and I really have big hopes that I will have the chance to change that."
World number one Novak Djokovic, whom Nadal could face in the semi-finals, comes up against German 16th seed Philipp Kohlschreiber.
The match is scheduled just before Nadal's on Court Philippe Chatrier, two days after Djokovic broke down in tears following the news his first coach had died.
French expectations will be on Richard Gasquet's shoulders as the men's seventh seed takes on Swiss ninth seed Stanislas Wawrinka.
Sloane Stephens, Jamie Hampton and Bethanie Mattek-Sands will be looking to join fellow American Serena Williams in the women's last eight.