The man, 33, was arrested in Scotland on the evening of Tuesday, October 21 nearly one week after the stabbing.
Sanchini, 27, was fatally stabbed in Rushey Green just after 3am on Wednesday, October 15.
Officers attended alongside the London Ambulance Service, who treated Sanchini for stab wounds.
He died later in hospital.
The suspect will be transferred to custody in London today and the police investigation is ongoing.
Detective Chief Inspector Rebecca Woodsford, leading the investigation, said: “Our dedicated team of detectives have worked tirelessly to locate and arrest this suspect.
“The work doesn’t stop here.
“We will continue to piece together the circumstances surrounding the tragic death of Sanchini as we strive to secure justice for him and his loved ones.”
If you have any information about the incident, contact police on 101 stating reference CAD635/15Oct.
You can also speak with independent charity Crimestoppers anonymously on 0800 555 111.
