Team World remain just two points behind their European rivals after a clean sweep in the night session of the Laver Cup made it 7-5 in Chicago.
Singles wins for Alexander Zverev and Roger Federer - over John Isner and Nick Kyrgios respectively - earlier in the day had Team Europe firmly in control, as they took a 7-1 lead before the evening matches.
Then, in a repeat of the Wimbledon final, Kevin Anderson, the runner-up in July, caused one of the biggest upsets of the tournament so far, beating Novak Djokovic 7-6 (7/5) 5-7 10-6.
The South African served his way out of trouble, while errors from Djokovic meant he again failed to put any points on the board after yesterday's doubles loss with Federer.
An energised crowd were then back out in force for the doubles showdown between Jack Sock and Nick Kyrgios and Grigor Dimitrov and David Goffin.
The American-Australian duo put in an entertaining performance - Kyrgios chest-bumping his red team at 4-3 in the second set.
Sock put the pair on match point with a superb volley, leaving Kyrgios to serve out the match and narrow Team Europe's lead to 7-5.
Three points per match are up for grabs on the final day, with the first team to 13 points lifting the Laver Cup 2018 trophy.
