The 24-year-old on Wednesday became the first Japanese man since 1918 to make the semi-finals in New York where he will face top-seeded Novak Djokovic.
But Chang, himself a Grand Slam title winner at the 1989 French Open, told the 10th seed that his work is not completed following his epic 3-6, 7-5, 7-6 (9/7), 6-7 (5/7), 6-4 quarter-final win over Australian Open champion Stan Wawrinka.
"He's telling me to stay focused in the match and never get frustrated too much and always pump up yourself," said Nishikori.
"He told me congrats on winning this battle. But he also says it's not done."
- Sports & Recreation
- Michael Chang
- Kei Nishikori
- Novak Djokovic