The tournament entered its fourth and final stage in Abu Dhabi and Royals made the most of home advantage to beat Manila Mavericks 26-25.
Victory ensures they stay within three points of leaders Aces, who beat Singapore Slammers earlier in the day at the Hamdan Sports Complex, with the competition's top two meeting on Friday.
Caroline Wozniacki laid the foundations for Royals' first win at their home venue, by brushing aside Kirsten Flipkens 6-2.
However, victories for Mark Philippoussis in the men's legends singles and Jo-Wilfried Tsonga in the men's singles reduced the deficit to two games.
Daniel Nestor and Flipkens helped reduced the arrears further with a 6-4 doubles triumph, but Nenad Zimonjic and Marin Cilic clinched the final game to give Royals the win that tees up Friday's potential title-decider nicely.
In the battle between top and bottom, Aces were largely comfortable in Thursday's early match as they wrapped up a 28-24 victory over Slammers.
Ana Ivanovic got the ball rolling with a hard-fought 6-5 win in the women's singles against Daniela Hantuchova before Fabrice Santoro maintained the momentum in the men's legends singles with victory over Pat Rafter.
The wins kept on coming for Aces as Rohan Bopanna and Sania Mirza took the mixed doubles, with Bopanna and Gael Monfils clinching the men's doubles.
Tomas Berdych gained Slammer's only victory of the set - sealing the victory 6-3 before adding extras in the Super Shootout.
However, it did not clsoe the gap sufficiently as Aces took another step closer to the title, breeding further confidence ahead of the much-anticipated encounter with Royals.
"We know there is pressure but we know what we have to do. That is to win," said Monfils.
"We will make it. All my team members are special, they give out a lot of positive energy and are all great."