SYDNEY, Australia (AFP) — Alex de Minaur has muscled up in a bid to bridge the gap on Jannik Sinner and Carlos Alcaraz, with the Australian aiming to be a "disruptor" to the pair's tennis dominance.

The world No. 7 is yet to beat either player and admits he has to find new weapons to challenge the Spaniard and Italian who have shared the last eight Grand Slam titles.

In contrast, De Minaur is yet to go beyond the last eight at a major.

"I've played some very close matches over the years with both of them and you feel like you're getting closer and closer," De Minaur told reporters in Sydney ahead of the season-opening United Cup starting Friday.

"You've got to work on your game, find new weapons.”

"For me, it's finding different ways to hurt these players and trying to be ready to take more risks and be a little bit more of a disruptor.”

"There are a couple of things here and there that we've tried to work towards in my team throughout this off-season to try to take the next step, and that's obviously the next goal."

One of the things De Minaur has been working on is body strength, employing a new fitness trainer as he prepares for the Australian Open in Melbourne on 18 January.

"I'm ultimately trying to get bigger and stronger and just keep on improving," he said.

"Over the years, I've gained a little bit of weight, which has definitely helped me.”

"There's no substitute for hard work, so that's what we'll be doing."

De Minaur secured one title last season in Washington, adding to his nine other career victories.

Australia faces the Czech Republic and Norway at the mixed-teams United Cup, which is also being played in Perth.