Cameron Norrie beat Dan Evans 7-6 (7-5) 7-6 (8-6) to record his second straight win over the British number one at the Battle of the Brits team competition.
Evans' emotions boiled over at times - bouncing his racquet off the court, dislodging a microphone and celebrating a net-cord point during the first set.
The 30-year-old was then 5-1 up and had set point in the second set before Norrie fought back to seal a great win.
Victory gives the British Bulldogs side a 22-11 lead over the Union Jacks.
British number three Norrie, 24, said: "It was tough. I was lucky to come through in the end and did well to come from 5-1 down.
"I was really pleased to get through that second-set tie-break. I was just trying to focus on my level. Credit to Evo [Evans] who came at me strong in that second set."
Earlier at Roehampton, British number two Heather Watson - competing for the Jacks - overcame a patchy first set to beat 24-year-old Eden Silva 3-6 6-1 10-6.
"Eden played very well - I barely remember her making any unforced errors," said Watson, 28.
"In the second set it really clicked for me, and in the [match deciding] tie-break it was anyone's. That was the first match tie-break we've won - I thought I've got to get one for the team."
Elsewhere, it was a disappointing start for the Broady family. Jacks team player Naomi Broady lost 6-3 6-2 to Beth Grey before younger brother Liam, competing for the Bulldogs, succumbed 6-3 6-4 to Jan Choinski.
The Battle of the Brits team event features the country's leading men and women at the National Tennis Centre, split into two groups chasing points in singles, doubles and mixed doubles matches.
The event has been organised by Jamie Murray to provide competitive action for British players while the professional tours remain suspended because of the coronavirus pandemic.
Wednesday's results
Union Jacks 11-22 British Bulldogs (first to 60)
(Matches show Union Jacks players first, with points available in brackets)
Centre court:
Heather Watson 3-6 6-1 10-6 Eden Silva (two)
Dan Evans 7-6 (7-5) 7-6 (8-6) Cam Norrie (two)
Court one:
Naomi Broady 3-6 2-6 Beth Grey (two)
Jan Choinski 6-3 6-4 Liam Broady (one)