Don't expect Australian tennis stars Sam Groth and Bernard Tomic to sit down for a beer any time soon.

Groth, who retired from professional tennis over the summer, appeared on Channel Nine on Sunday morning to talk about the first-round French Open clash between Tomic and fellow Aussie Nick Kyrgios.

Asked how he gets along with Tomic, Groth was careful with his words.

"We don't hang out too often," he said.

"We get along fine, but I'm a little bit older than him.

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"I'm not going to go down to the pub with him for a beer."

Groth, 30, didn't comment any further about their relationship, but when asked about Kyrgios, said the Aussie bad-boy has matured.

"I think he's been harshly judged for some of the stuff he's done on the court," Groth said.

"If he hadn't had that run in with Stan Wawrinka a few years ago, I don't think we'd be putting him in the spotlight he's been in.

"Everyone makes mistakes on the tennis court. Everyone makes mistakes on the footy field.

"He is (maturing). He is. He has his foundation and at the Davis Cup, if there's kids around, he's the first one to interact with the kids. He's great with all that stuff.

"He's maturing on the court and only time will tell how we judge him on his career."

On the first-round French Open match between them, Groth gave Kyrgios the edge, but said there are questions over the 23-year-old's fitness.

"Nick should win - he won a doubles title last night in Lyon, but he still said he's progressing in his rehab," he said.

"He said he's only about 80 percent, so I don't know if he's giving himself just a little out in case things go bad.

"He hasn't played since April.

"They come in with vastly different preparations. Nick hasn't played in six weeks - he played doubles - but it's a different proposition playing the best of two sets in an ATP event to the singles at Roland Garros."

On the other hand, said Groth, Tomic doesn't have any expectations on his shoulders.

"Bernie's come in and made a Challenger final and then he's qualified," Groth said.

"So he's already got three matches under his belt at the courts that they're going to play on.

"He's got nothing to lose. None of the pressure is on Bernie. It's all on Nick.

"Everyone expects Nick to win and no one even thought Bernie was going to be in this tournament."