Security personnel acted quickly to drag the man off the court before play resumed following a quick check of the surface which was not damaged during the bizarre incident.
British media reported that the protestor was a member of the End UK Private Jets group, which claims "carbon emissions in 2022 are genocide."
Tsitsipas went on to win the match 6-2 6-1 to give Team Europe a 2-0 lead over the Rest Of The World in the competition after Casper Ruud (23) had earlier beaten Jack Sock (29) 6-4 5-7 10-7.
Swiss great Roger Federer (41) is due to take to the court later in the day for the final match of his career, partnering his great rival Rafael Nadal (36) to face the American duo of Sock and Frances Tiafoe (24).