Grigor Dimitrov was about to serve at Wimbledon when two environmental activists jumped out of the stands at Court 18 and disrupted his match by scattering orange confetti and puzzle pieces on the grass. His initial instinct? Get involved and try to stop them.

"But then I also realised,” the three-time Grand Slam semifinalist said on Wednesday, "that's not my place to do that."

Instead, security guards hauled away the woman and man wearing T-shirts from Just Stop Oil — an organization that wants the British government to stop new oil, gas and coal projects — and the two were arrested "on suspicion of aggravated trespass and criminal damage," according to the All England Club.

The next contest on that same court, best known as the site of John Isner's 2010 victory over Nicolas Mahut in the longest match in tennis history, was also interrupted by another man from that same environmental group. He was corralled by two security guards and was arrested, too, the club said.

"Obviously it's not pleasant," said Dimitrov, a 32-year-old from Bulgaria who is seeded 21st in the men's bracket and ended up beating Japanese qualifier Sho Shimabukuro 6-1 6-2 6-1.

"In the end of the day, there is not much you can do. I think everyone in a way did their part as quick as possible."

The second match that was affected was British wild-card entry Katie Boulter's 7-6(4) 6-2 win against Daria Saville of Australia. Boulter and Saville helped clean up the debris before their match resumed.

As it happened, a rain delay came as the court was cleared after the interruption of Dimitrov's match.

He said he did not feel threatened by what happened.

But Dimitrov did acknowledge there is a sense of vulnerability for players.

"You're just out there, in a way," Dimitrov said.

"And also: The security are checking the bags when (people) are entering the grounds, but you just never know what the person might do."

The All England Club coordinated with London police and other agencies to increase security for this year's tournament, in part as a result of protests at other major sports venues in Britain this year.

"Based on what has happened at other sporting events, and on the advice from our key partners, we have reviewed our security plans, which have now been uplifted for The Championships accordingly," All England Club operations director Michelle Dite said last week.

"We have plans in place to mitigate the risks working in partnership with specialist agencies and the Metropolitan Police and should an incident occur, the appropriate specialist teams will respond," Dite said.

Her comments came a day after people representing Just Stop Oil briefly disrupted play about five minutes after the start of a cricket match between England and Australia in London. Players from both teams intervened when the protesters attempted to spread orange powder on the field.

Earlier in June, protesters held up the England cricket team bus briefly during the test against Ireland in London. Activists also have targeted Premier League soccer matches, the Premiership rugby final at Twickenham, and the world snooker championship in Sheffield this year.

"I guess, in some ways, it would be a bit of a distraction if it was going on during the match, but I also understand the importance, too, sometimes, of people being able to protest for things that matter for them. And especially anything related to the climate," said American Danielle Collins, who won her first-round match at Court 17 on Wednesday.

"This is a real thing that we're dealing with, and I feel like not enough people are aware of those issues and have enough education around it."