Dual grand slam finalist Mark Philippoussis says Alex de Minaur needs to "get outside his comfort zone" if he wants to finally knock off big dogs Carlos Alcaraz and Jannik Sinner.
Facing Alcaraz in the Australian Open quarter-finals on Tuesday, De Minaur will need to end a 0-5 run of career losses against the world No.1 Spaniard while he's winless in 13 matches against two-time Melbourne Park champion Sinner.
Former ace Philippoussis has been impressed by the top-ranked Australian's charge into the final eight but says he will need to take more risks to cause a boilover.
He said against the world's two best players, de Minaur couldn't rely on his trademark style of grinding down his opponents.
"Alex is playing some great tennis - he's looking strong, moving well, mentally and physically as strong as ever," said 'Scud', who made the finals at Wimbledon and the US Open.
"But I believe that if he wants to try and get that first win over the boys, like an Alcaraz or a Sinner, he's going to have to play outside of his comfort zone.
"And what I mean by that is he's going to have to just be willing to take on more risk on the important points."
The 49-year-old said he wanted to see sixth seed play with more aggression, which could involve attacking the net.
In the Laver Cup ATP Tour Finals last year de Minaur used the tactic with great success.
"It is an important part of his game - obviously, it's not a natural part of his game to move forward, but by moving forward, by playing outside of your comfort zone, by stepping up and taking some risks, going forward is one part of it," the former Davis Cup hero said.
"Because he's got great volleys, fantastic volleys, he's got great technique so when he's up there, he's comfortable.
"Doing that consistently is one thing, but doing it where you're keeping your opponent off balance is another thing as well.
"Giving someone like an Alcaraz rhythm is a very dangerous thing ... so you want to do something where you put him a little bit off balance to keep him guessing."
Philippoussis said he's noticed the growth in the game of de Minaur in the past 12 months and believed Alcaraz and Sinner were beatable.
"They're not robots - look at Sinner the other day, he was very, very lucky to survive and he's someone that we saw does struggle in the heat," he said.
"So, you know, they're all vulnerable, anything can happen on the day ... Alex should definitely be stepping on court believing he can win no matter who he's playing. He has the game to do that."
