Nick Kyrgios has a new secret weapon behind the scenes but he's not telling who it is.
Kyrgios gave his Australian Open preparations a massive confidence boost with an upset 6-4, 7-6 (7-5) win over world No2 Andy Murray at the Hopman Cup.
Murray eliminated Kyrgios from three of the four Grand Slams in 2015.
But Kyrgios had all the answers in their showdown at Perth Arena, with the world No 30 revealing afterwards he received plenty of tips from a mystery adviser.
"I don't have a coach, but I did get certain tips from a certain someone before the match," Kyrgios said.
"I'm not going to tell you who that is. Hopefully that can continue to come, and she can keep giving me tips."
Retiring veteran Lleyton Hewitt has been mentoring Kyrgios in recent months. But the fact Kyrgios referred to a "she" raised questions as to who is helping him behind the scenes.
But if there really is someone behind the scenes giving him vital tips, they're working wonders.
Kyrgios played out of his skin against Murray.
And even though he got sucked into some verbal barbs from a member of the crowd, he managed to get his mind back on task to seal the win during the second-set tiebreak.
Kyrgios played a key role in the mixed doubles win to lift Australia Green to a 2-1 win over Great Britain.
The result means Australia Green will secure a spot in tomorrow's final if they beat France tonight.
Murray appeared troubled by a right thigh injury during his singles loss. But he played down the injury after the match.
"It was just the same thing as the other day," Murray said.