Nelly Korda might not have planned to wake up at 4:15 to watch her brother play in the Australian Open, but when your sibling is facing one of the biggest matches of his life, sometimes your body just knows.

Nelly hoped she’d wake up to the news that Sebi had bested world No. 8 Daniil Medvedev in the third round. Instead, she got to watch her younger brother win in straight sets.

“I saw him win in dining, so that was cool,” Nelly said Friday at the Hilton Grand Vacations Tournament of Champions. “I did actually wake up 30 minutes before my alarm to watch him play, just naturally knowing that he was playing.”

Honestly, he's put in a bunch of work. He has an amazing support system behind him, and it's really cool and special to see him do what he's doing. Hopefully he can continue making this run. But from an outside point of view, it's really special seeing him achieve all this, and I couldn't be happier for him.”

Sebi, whose full name is Sebastian, didn’t shy away from highlighting his family’s achievements after the win, even if it was at his own expense.

After he pointed out that both of his sisters, Nelly and Jessica, and his dad, Petr, have won an Australian Open, the interviewer poked a little fun at the 22-year-old.

Interviewer: “So that means you’ve been underachieving for a little while, is that right?”

Sebi: “You know, I don’t know what I’m going to be ranked, but my mom’s career high was 24, my dad’s was 2, Nelly was No. 1, my oldest sister, Jessica, was 6, so I’m definitely the worst athlete in the family so far.”

To that statement, Nelly calls “complete BS.”

“Honestly, he’s the best,” his older sister responded when asked if that was true. “His hand-eye coordination is unbelievable. His swing – I’m jealous of his swing actually. It’s crazy. He’s a lefty. He’s a natural righty, but he plays golf lefty. He played hockey lefty. I mean, he grew up playing hockey. He was pretty good at it, too. He skates really nicely, plays golf nicely, plays tennis beautifully.”

Nelly isn’t over-exaggerating about Sebi’s athletic prowess either.

While the youngest Korda picked up ice hockey at the age of 3, he decided to switch to tennis at the age of 9 after going to the 2009 U.S. Open with his dad. Just two years later, at the age of 11, he won a golf tournament in Prague.

So how’s Sebi’s golf swing today?

“It's funny; he swings it lefty, which is really nice,” Nelly said. “He doesn't change his hands, and he swings it righty and still pures it. Yeah, it's just, he's special. He's one of a kind. He's really talented.”

More Korda dominance could be mere days away. Sebi will try to keep his run Down Under alive on Saturday when he faces 10th seed Hubert Hurkacz in the fourth round. Stateside, Nelly is sitting solo 2nd heading into the weekend at Lake Nona.