Juan Martin del Potro said that he was battling illness after he suffered a shock defeat in the China Open final on Sunday, losing 6-4, 6-4 to unseeded Nikoloz Basilashvili of Georgia.
Argentine top seed Del Potro was far from his best and has been fighting flu or a cold for several days in the Chinese capital.
The world number four said that he did his utmost in difficult circumstances.
Basilashvili Reigns In Beijing! ??
— ATP World Tour (@ATPWorldTour) October 7, 2018
The ?? wins three straight games to stun Juan Martin del Potro 6-4, 6-4 and capture his second ? of the season in Beijing. pic.twitter.com/Gz4R4QVExV
"I did everything that I can to be better for the final, it wasn't enough time to feel 100 percent," the 30-year-old said.
"As you can see, my game today wasn't as good as it was in the last matches in the tournament. I had some problem the last three days and it affected a little bit my game."
Del Potro, who reached last month's US Open final and is enjoying one of the best seasons of his injury-interrupted career, is now in a race to be better for this week's Shanghai Masters.
#tennis: Unwell Juan Martin del Potro suffers shock defeat in #ChinaOpen2018 final https://t.co/SZZwevLDPY pic.twitter.com/rkOtrzZ5VB
— The Field (@thefield_in) October 7, 2018
"I wasn't able to play with that fire that I have in all my matches," Del Potro added, saying however that 34th-ranked Basilashvili "played unbelievable".
It is only the second title of 26-year-old Basilashvili's career, having won his maiden ATP title in Hamburg in July.
? No. 2 for @nikolozbasilash!
— US Open Tennis (@usopen) October 7, 2018
Coming off a R4 showing at the #USOpen, the ?? stuns Del Potro 6-4, 6-4 to capture the title in Beijing!
?: @ChinaOpen pic.twitter.com/oqtXiIfgrf
"Playing against Juan, he was sick today for sure, I could see that," said the all-action Georgian.
"But he put me in really tough situations. I needed to really work it, to work hard, win the points."