Coco Gauff revealed her frustration after her unbeaten start to 2013 was ended as the seventh seed bowed out of the Australian Open to Jelena Ostapenko in the fourth round on Sunday.

The 18-year-old American came into the Melbourne event fresh from victory at the Auckland Open but had not dropped a set in her three Australian Open victories, including toppling Emma Raducanu in the second round.

Gauff enjoyed a strong 2022 season that included reaching the US Open quarter-finals and finishing runner-up at the French Open.

But on Sunday, 2017 French Open champion Ostapenko triumphed 7-5 6-3 in one hour and 34 minutes, ending Gauff's Australian Open campaign, leaving the teenager in tears as she explained her frustration.

"I felt really good coming into the tournament, and I still feel good," Gauff told reporters. "I still feel like I've improved a lot but when you play a player like her and she plays really well, you know there's nothing you can do.

"I feel like today I would say nothing because every match you play a part in, but I feel like it was rough, so it's a little bit frustrating on that part."

Ostapenko hit 30 winners compared to Gauff's 21, while the Latvian did commit more unforced errors (27-14).

Gauff generated eight break points throughout the match but only took one, while Ostapenko took all three of hers.

"Today I learned a lot," Gauff said. "A little bit frustrated, but I think I'll rewatch and see where I went wrong and if I did go wrong.

"I feel like from the feedback I've gotten that she just played really well today. She stepped up her game when she needed to, and she held and broke me when she needed to, and I didn't do that."

Ostapenko progresses to the quarter-finals where she will take on 2022 Wimbledon champion Elena Rybakina who knocked off top seed Iga Swiatek.