The Japanese star recovered from a dreadful start to beat veteran Spaniard Fernando Verdasco 0-6, 6-4, 6-4, 6-0 in the French Open fourth round to reach a seventh Grand Slam quarter-final.
Nishikori surpassed Jiro Satoh for the most quarter-final appearances by a Japanese man, as he made the last eight for the second time in three years in Paris.
He will take on Murray for a place in the semi-finals, with the Briton prevailing in eight of their 10 previous meetings.
"Sorry that I don't remember much," Nishikori responded when asked of the confidence he could draw from that five-set victory.
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"You know when we play it's always a battle," he added. "Yeah, for sure, it's gonna be a tough one.
"We have been playing so many times. He's great player. Very smart tennis player. It's never easy, and I think this week he's been playing well."
Verdasco knocked out German ninth seed Alexander Zverev in the first round and looked like claiming another top-10 scalp when he raced through the opening set.
"I couldn't do anything first set but I tried to play deeper and more aggressive, and little by little I got better today.
"But still it was really, really tough battle. There was so many long rallies, second and third sets. I don't know how I got the second and third.
"The fourth, I think it was perfect tennis I played. So, yeah, very tough battle but very happy to win today."
Nishikori was playing for the third day running after his last-32 clash with South Korea's Hyeon Chung was held up by rain.
Murray, who coasted into the last eight with a straight- sets win over Russia's Karen Khachanov, knows Nishikori will represent his biggest test so far.
"Kei, you know, obviously lost against him at the US Open. He plays well on the clay. You know, very solid off both wings. Moves well, quick," said Murray.
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