Kyrgios's brilliant gesture for rookie De Minaur

Lleyton Hewitt has lifted the lid on an awesome Nick Kyrgios gesture for Alex De Minaur in Davis Cup camp.

De Minaur, 18, was thrust into his debut Davis Cup campaign in a massive show of faith from captain Lleyton Hewitt.

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The teenager came up agonisingly short of an incredible upset over World No.5 Alexander Zverev on Friday, falling in five thrilling sets.

After the match, Hewitt revealed how Kyrgios had taken De Minaur under his wing during camp in Brisbane.

"He's been fantastic with De Minaur," Hewitt told Channel 7.

"He's sort of been his older brother.

"Even when Alex was the orange boy (in previous campaigns), he'd always get him out to hit with him and help him."

Hewitt also spoke of Kyrgios's growing maturity and how the team environment of Davic Cup brings out the best in him.

"They're the things that the public doesn't see Nick Kyrgios do," Hewitt said.

"He's had to grow up very quickly in the spotlight.

"I think he's really matured over the last six months and I think the Davis Cup has helped that."

Kyrgios has been heavily criticised in the past but seemed to win over a large number of fans during the Australian Open.

He showed a newfound calmness on court, while also displaying his softer side while away from it.

He regularly invited disadvantaged kids to hit with him on the practice court and continues to do some brilliant work with the Nick Kyrgios Foundation.