The Princess of Wales has attended Wimbledon on a day that Aussie giant slayer Maya Joint’s adventures went up in smoke while Alex de Minaur kept the green-and-gold flag flying.

Kate, who is patron of the All England Lawn Tennis Club, broke with tradition by sitting on the outside courts instead of the royal box.

She also chatted with diehard tennis fans lined up outside for a last-minute ticket, and tried her hand in the ticket office.

Dressed in a blue linen suit, the princess took her seat in the stands at Court 18 next to former semi-finalist Tim ‌Henman.

Later, she sat in court one beside former world No.1 Sir Andy Murray as they watched Briton Katie Swan against American Madison Keys.

The future queen’s attendance on day four of the tournament coincided with two Aussies playing.

Alex de Minaur saw off potentially troublesome French veteran Adrian Mannarino 6-3 6-2 6-2 on Thursday morning.

Afterwards, Aussie No.1 Maya Joint took to the same court three with high hopes of building on her monumental first-round victory over Serena Williams.

But faced with another big crowd again screaming largely for her opponent, Joint saw her brilliant start slip tamely away as Alexandra Eala, a young heroine in the Philippines, roared back to defeat her 3-6 6-2 6-0.

With James Duckworth and Kim Birrell later both being defeated by seeded players, it left the now-familiar firm of de Minaur and Daria Kasatkina as the last two Australians standing in the singles of the original 13-strong contingent.

The US-born Queenslander Joint had grabbed headlines around the world for her defeat of 44-year-old Williams on Centre Court, eventually outstaying the legend who ended up struggling with the pace and physicality of the match.

But 21-year-old Eala, defeated by Joint in an epic final on the Eastbourne grass last year, proved a different proposition. She only got more dominant in the latter stages of her revenge mission, reeling off the final nine games to prevail in three minutes under two hours.

Joint, who had begun in the same exhilarating manner in which she’d finished against Williams, seemed to have the match on her racquet, striking 37 winners in all with her initially crisp ball-striking.

But it all started to unravel in the second set as the mistakes began to flow from the Australian, who ended up making 41 unforced errors. With each one, the volume from the legion of Filippino fans who follow their “Alex” everywhere began to crank up.

“I really had to dig deep after Maya came out on fire, she came out ready,” said a beaming Eala as she addressed the cheering crowd.

“She is coming off an amazing win against Serena. She played really well and handled herself really well in that situation, so congratulations to Maya.”

Earlier, de Minaur needed just one hour 49 minutes to see off the often tricky 38-year-old left-hander Mannarino.

De Minaur won the first two sets in 38 minutes each, breaking twice in the first set and three times in the second despite his serve occasionally malfunctioning. He was broken once in each stanza, but there was no such blemish in the third.

He broke his downcast opponent twice more to set up a third-round meeting with American Zachary Svajda, who defeated de Minaur’s recent s’Hertgenbosch final conqueror Kamil Majchrzak 2-6 6-2 6-7 (5-7) 6-4 6-3.

The rising world No.66 Svajda won’t be a pushover for “Demon”, having recently knocked out two Australians, Alexei Popyrin and Adam Walton, at the French Open.

“I’m very happy with a very clean performance today. I think going in, it was a very tricky match-up, and I did what I needed to do,” said de Minaur.

“There were some tough moments here and there, but I thought my serve got me out of trouble in certain key moments.

“I just love it here and I’m hoping I can stay here for a long time.”

Duckworth, also on court three, found French Open finalist Flavio Cobolli too tough, but only after giving the charismastic Italian No.9 seed a run for his money in a 7-6 (7-4) 3-6 7-6 (7-3) 6-1 defeat.

The match was still in the balance until the Italian played a blinding breaker in the third set, which finally seemed to crush Duckworth’s resolve.

Queenslander Birrell also couldn’t cope with the veteran Romanian No.17 seed Sorana Cirstea in their evening clash, losing 6-3 6-4 in 71 minutes.

-with AAP