Jamie Murray and Heather Watson levelled the Battle of the Brits team event going into the final day after a thrilling win in the mixed doubles.
Murray and Watson, playing for the Union Jacks, won 6-3 3-6 17-15 against British Bulldogs pair Liam Broady and Harriet Dart in Roehampton.
The Union Jacks have trailed throughout the week-long competition, but are now level at 45-45 going into Sunday.
The first team to reach 60 points will triumph at the National Tennis Centre.
"The match tie-break was brutal, it was pretty much neck and neck the whole way," said 34-year-old Murray.