In what is likely to be the Spaniard’s final appearance in Rome, Nadal, 37, was comfortably beaten 6-1 6-3 by the big-serving Pole in just 93 minutes.
Nadal, a 10-time winner in the Italian capital, has indicated that 2024 is likely to be his final season before retirement.
The 14-time French Open champion says he is yet to decide whether to play at Roland Garros this year. This year’s tournament starts on 26 May.
“The decision, as you can imagine, is not clear in my mind today,” Nadal said.
“But if I have to say what’s my feeling and if my mind is closer one way or the other way, I’m going to say ‘be in Roland Garros and try my best’.
“Physically, I have some issues, but not probably yet enough to say not playing in the most important event of my tennis career.”
Elsewhere, Polish world number one Iga Swiatek booked her place in the women’s last 16 with a 6-3 6-4 win over Yulia Putintseva.
Swiatek came from 4-1 down in the second set to extend her winning streak to eight matches, and will take on Angelique Kerber in the next round after her straight-set win over Aliaksandra Sasnovich.
Naomi Osaka has still not dropped a set in the tournament so far after beating Daria Kasatkina 6-3 6-3.
The Japanese former world number three plays the winner of Linda Noskova and Qinwen Zheng next.
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