Andy Murray helped his team reduce a huge deficit in the Battle of the Brits Team Tennis with a dominant win in the doubles alongside Lloyd Glasspool.
Murray and Glasspool, playing for the Union Jacks, beat British Bulldogs pair Alastair Gray and Dom Inglot 6-4 6-4 at the National Tennis Centre.
The Union Jacks trailed 29-12 going into day four but won seven of the nine matches on Thursday.
Jamie Murray and Heather Watson's mixed doubles win cut the gap to 31-25.
The doubles victories followed Watson's 6-2 6-4 success against 17-year-old Emma Raducanu, with further wins in the singles for Jodie Burrage, Jan Choinski and Anton Matusevich.
Kyle Edmund rallied from a set down to beat Ryan Peniston and earn only the Bulldogs' second point of the day, following Maia Lumsden's win over Naomi Broady earlier on Thursday.
The country's leading men and women are playing together in singles, doubles and mixed doubles matches in a week-long competition.
It has been organised by Jamie Murray to provide competitive action for British players while the professional tours remain suspended because of the coronavirus pandemic.
The first to 60 points will win the event, which features 40 singles and 20 doubles matches and finishes on Sunday.
Murray and Watson continue preparations with wins
Andy Murray, who has been dealing with pelvic and shin injuries in recent months, is playing only in the doubles because he does not want to "take any risks" with his fitness.
The three-time Grand Slam champion is planning to play in the Cincinnati Masters and US Open double header, which is set to take place behind closed doors in New York in August.
The Scot, 33, showed glimpses of undoubted quality throughout the doubles match, including a crosscourt forehand winner from the baseline which clinched victory.
"I was happy, played well, returns were good, served pretty well. It was a good performance from both of us," said Murray.
Watson, 28, continued her preparations for the resumption of the WTA Tour by winning her third singles match of the week.
"I have been saying after each of my previous matches that I have been getting better and better after each match," said Watson, who won the Acapulco title in one of the final tournaments before the WTA Tour was suspended in March.
"It was a big jump, I definitely played some really good tennis.
"This is my first week of playing matches since the pandemic begun, it is getting that match practice in and getting used to the stress of playing a match again. I am dealing with it better and I am feeling better."
Union Jacks 25-31 British Bulldogs (first to 60)
(Matches show Union Jacks players first)
Jodie Burrage 5-7 6-4 10-6 Harriet Dart (two points)
Heather Watson 6-2 6-4 Emma Raducanu (two points)
Andy Murray/Lloyd Glasspool 6-4 6-4 Dom Inglot/Alastair Gray (two points)
Ryan Peniston 7-6 (7-2) 5-7 6-10 Kyle Edmund (one point)
Jamie Murray/Heather Watson 6-4 6-4 Joe Salisbury/Emma Raducanu (three points)
Naomi Broady 3-6 5-7 Maia Lumsden (one point)
Jan Choinski 6-2 6-3 Liam Broady (one point)
Anton Matusevich 6-3 1-6 10-6 Aidan McHugh (one point)
Olivia Nicholls/Alicia Barnett 6-4 6-3 Eden Silva/Beth Grey (two points)