Rafael Nadal has tested positive for Covid-19 after returning home from the Mubadala World Tennis Championship in Abu Dhabi.
Nadal said he had experienced some "unpleasant moments" but hopes to improve "little by little".
The 35-year-old has only just returned to action after a long injury lay-off.
Nadal wrote on Twitter: "On my return home after playing the Abu Dhabi tournament, I have tested positive for Covid in the PCR test that was performed on me when I arrived in Spain.
"Both in Kuwait and Abu Dhabi we passed controls every two days and all were negative, the last being on Friday and having the results on Saturday.