Andy Murray's preparations for the restart of the professional tour continued at the Battle of the Brits Team Tennis - but ended in a mixed doubles defeat with Jodie Burrage.
Former world number one Murray and Burrage were beaten 4-6 6-4 10-8 by Joe Salisbury and Emma Raducanu.
Salisbury and Raducanu's win gave their British Bulldogs side a 18-8 lead over the Union Jacks at the end of day two.
Earlier, Johanna Konta found her rhythm to fight back and beat Katie Boulter.
Murray, who has been dealing with pelvic and shin injuries in recent months, is playing only in the doubles at the National Tennis Centre 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 next month.
What is the Battle of the Brits? And who is playing?British number one Konta, playing in only her second match since the WTA Tour was suspended in March because of the coronavirus pandemic, won 2-6 7-6 (7-5) 10-6 in Roehampton.
The 29-year-old lost her opening match against 21-year-old Burrage on Monday and trailed by a set and double break against former world number 89 Boulter before the rustiness wore off.
Bulldogs' Cam Norrie, Liam Broady and Maia Lumsden also won their singles matches, while Harriet Dart and Beth Grey claimed victory in the doubles to help open up a 16-5 lead.
Union Jacks' Dan Evans beat Kyle Edmund 6-4 6-4 in a match worth three points before Salisbury and Raducanu extended the advantage against Murray and Burrage.
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.
"It's not what it would feel like at a Grand Slam or WTA event but it was good to give both of us the chance to get those competitive juices and pretend we're somewhere else," said Konta after beating 23-year-old Boulter.
"These are my first competitive matches since the beginning of March so it is going to take time. I was in a good mindset and I stayed in each point and gave myself the best chance for my level to get better."
Tuesday's results
Union Jacks 8-18 British Bulldogs (first to 60)
(Results show Union Jacks players first, with points available in brackets)
Centre court
Jan Choinski 4-6 3-6 Cameron Norrie (two)
Katie Boulter 6-2 6-7 (5-7) 6-10 Johanna Konta (one)
Naomi Broady/Heather Watson 2-6 4-6 Harriet Dart/Beth Grey (two)
Dan Evans 6-4 6-4 Kyle Edmund (three)
Andy Murray/Jodie Burrage 6-4 4-6 8-10 Joe Salisbury/Emma Raducanu (two)
Court one
Anton Matusevich 1-6 6-2 10-12 Liam Broady (one)
Alicia Barnett 7-5 4-6 7-10 Maia Lumsden (one)
Jamie Murray/Olivia Nicholls 7-6 (7-4) 6-4 Alastair Gray/Eden Silva (one)