A protester set his hand on fire after running onto the pitch and briefly stopping play during the Laver Cup at the O2 Arena in London.
The young man, who was wearing a T-shirt with the message ‘The end of private jets in Great Britain’, was quickly removed by security and locked in an inner corridor.
Laver Cup organizers said he was arrested and the police are looking into it.
The incident happened before the second set of the match between Stefanos Tsitsipas and Diego Schwarzman.
“It came out of nowhere,” said Greek world number six Tsitsipas. “I’ve never had an incident like this on the field. I hope he’s okay.”
It is the latest security breach at a tennis tournament following incidents at the Australian Open and French Open earlier this year.
A protester, carrying a banner reading ‘End refugee detention’, jumped onto the court during the Australian Open singles final between Rafael Nadal and Daniil Medvedev in January.
In May, a protester stopped the semifinals of the French Open Championship between Casper Ruud and Marin Čilić. She went to Philippe Chatrier’s court, knelt by the post of the net, tied something around her neck and attached it to the net.
There was a brief delay of around five minutes before the Laver Cup match resumed in London on Friday.
Tsitsipas, who played for Team Europe, had just won the first set and the Greek went on to celebrate 6-2 6-1.
The win gave Europe a 2-0 lead on the first day of the three-day team event after world number two Ruud won 6-4 5-7 10-7 against Jack Sock in the first match on Friday.
Former British world number one Andy Murray then had the chance to guarantee Europe’s lead at the end of day one.
But the 35-year-old Scot lost 5-7 6-3 10-7 to Australia’s Alex de Minaur, who closed the gap on the world team to 2-1.
In Friday’s final match, Swiss great Roger Federer brings his illustrious career to a close.
The 41-year-old, who has since retired, plays alongside Spain’s Rafael Nadal in the doubles match against Sock and fellow American Frances Tiafoe.