Liverpool forward Sadio Mane's house was burgled while he was playing in the Champions League last-16 tie against Bayern Munich on Tuesday.
The incident happened at Mane's house in Allerton, south Liverpool between 18:00 and 23:45 GMT - while the 26-year-old was at Anfield. No-one was in the property at the time.
Items including watches, mobile phones and car keys were stolen.
Forensic examinations are under way and a police investigation is ongoing.
Detective Inspector Phil Mahon, of Merseyside Police, said: "We are appealing for anyone with information in relation to this burglary to please come forward and assist our inquiries.
"While the occupants were not present at the time of the incident this will no doubt be a distressing experience for them and I would ask the offenders to do the right thing and return the stolen items to the owner in any way possible.
"We know the watches in particular are of significant monetary value and I would also like to appeal to anyone who might have been offered the items for sale since the burglary to contact police."
Senegal international Mane was burgled in November 2017 while he was at Anfield for a Champions League game against Maribor.
A gang was thought to have broken into his home first before smashing a patio door at the nearby address of team-mate Dejan Lovren before they fled when a woman shouted she was calling the police.