A protester set his arm on fire after running on court and briefly stopping play during the Laver Cup at the O2 Arena in London.
The young man, wearing a T-shirt with the message 'End UK private jets', was quickly removed by security and detained in an internal corridor.
Laver Cup organisers said he had been arrested and police were "handling" it.
The incident happened before the second set of the match between Stefanos Tsitsipas and Diego Schwartzman.
"It came out of nowhere," said Greek world number six Tsitsipas. "I never had an incident like this happen on court. I hope he is all right."
It is the latest security breach at a tennis tournament following incidents at the Australian Open and French Open earlier this year.
A male protester, carrying a banner which read 'Abolish refugee detention', jumped on to the court during the Australian Open men's singles final between Rafael Nadal and Daniil Medvedev in January.
In May, a female protester interrupted the French Open semi-final between Casper Ruud and Marin Cilic. She walked on to Court Philippe Chatrier, knelt beside the net post, tied something around her neck and fastened it to the net.
In London on Friday, there was a short delay of about five minutes before the Laver Cup match resumed.
Tsitsipas, playing for Team Europe, had just won the opening set and the Greek went on to clinch a 6-2 6-1 victory.
The win put Europe 2-0 ahead on day one of the three-day team event after world number two Ruud won 6-4 5-7 10-7 against Jack Sock in the opening match on Friday.
Britain's former world number one Andy Murray then had the opportunity to guarantee a lead for Europe at the end of the opening day.
But the 35-year-old Scot lost 5-7 6-3 10-7 to Australia's Alex de Minaur, who reduced the deficit for Team World to 2-1.
Friday's final match sees Swiss great Roger Federer bring his illustrious career to an end.
The 41-year-old, who is retiring afterwards, plays alongside Spain's Rafael Nadal in a doubles match against Sock and his fellow American Frances Tiafoe.
Laver Cup organisers said he had been arrested and police were "handling" it.
The incident happened before the second set of the match between Stefanos Tsitsipas and Diego Schwartzman.
"It came out of nowhere," said Greek world number six Tsitsipas. "I never had an incident like this happen on court. I hope he is all right."
It is the latest security breach at a tennis tournament following incidents at the Australian Open and French Open earlier this year.
A male protester, carrying a banner which read 'Abolish refugee detention', jumped on to the court during the Australian Open men's singles final between Rafael Nadal and Daniil Medvedev in January.
In May, a female protester interrupted the French Open semi-final between Casper Ruud and Marin Cilic. She walked on to Court Philippe Chatrier, knelt beside the net post, tied something around her neck and fastened it to the net.
In London on Friday, there was a short delay of about five minutes before the Laver Cup match resumed.
Tsitsipas, playing for Team Europe, had just won the opening set and the Greek went on to clinch a 6-2 6-1 victory.
The win put Europe 2-0 ahead on day one of the three-day team event after world number two Ruud won 6-4 5-7 10-7 against Jack Sock in the opening match on Friday.
Britain's former world number one Andy Murray then had the opportunity to guarantee a lead for Europe at the end of the opening day.
But the 35-year-old Scot lost 5-7 6-3 10-7 to Australia's Alex de Minaur, who reduced the deficit for Team World to 2-1.
Friday's final match sees Swiss great Roger Federer bring his illustrious career to an end.
The 41-year-old, who is retiring afterwards, plays alongside Spain's Rafael Nadal in a doubles match against Sock and his fellow American Frances Tiafoe.