Katie Boulter won’t be in the stands for Alex de Minaur’s quarter-final.

Katie Boulter won’t be able to support Alex de Minaur in person (Image: Eurosport)

Alex de Minaur will play one of the most important matches of his career as he meets Jannik Sinner in the Australian Open quarter-final.

The world No. 8 has never made it this far at his home Grand Slam tournament. And he’s hoping to go even further to keep Australia’s hopes alive in the men’s singles draw.

But one of his biggest supporters, fiance and British No. 1 Katie Boulter, won’t be in his box for the crucial match, after jetting back home to the UK.

De Minaur and Boulter are one of the sport’s power couples. They started dating almost five years ago and got engaged during the off-season.

The pair have been melting hearts in Melbourne Park this fortnight, racing to watch each other in action after finishing their own matches. After crashing out in the second round, Boulter stuck around to continue supporting her partner.

The WTA No. 25 was in the stands of Rod Laver Arena to watch De Minaur break new ground at the Australian Open on Monday, cheering him on as he beat Alex Michelsen in the last 16.

Alex de Minaur faces reigning champion Jannik Sinner in his first Australian Open quarter-final (Image: Getty)

But she won’t be there for his first appearance in the quarters, as retired British star Laura Robson revealed that Boulter had flown home to prepare for her next tournament.

“Unfortunately Katie isn’t here, she’s gone home,” Robson – who is one of Boulter’s good friends – told Eurosport.

“She left yesterday morning because she’s playing Doha in a couple of weeks so needs to be able to prepare as best as possible for that. But I know she’ll be watching on the TV.”

Boulter got a special shoutout last time she turned up to watch De Minaur play. After he reached the Aussie Open last eight for the first time, Jim Courier suggested the Brit had something to do with it.

“First time in the quarter-finals and I’m just wondering, you just got engaged, is that a coincidence that it’s all happening now?” Courier joked while interviewing De Minaur on the court.

“I don’t believe in coincidences! I think when you’re happy off the court you play some good tennis on the court,” the No. 8 seed smiled.

While he won’t have Boulter in his box, De Minaur will have the 14,800-strong crowd on Rod Laver Arena rooting for him.

He’s the first Australian man to reach the quarter-final in Melbourne Park since Nick Kyrgios a decade ago. Before that, Lleyton Hewitt made it to the final in 2005.

There hasn’t been a home champion in the men’s singles event since 1976, when Mark Edmondson became the lowest-ranked Grand Slam winner at No. 212 in the world.