Eala Mania is still going strong -- 'cause tennis phenomenon Alex Eala's Nike merch went live on Tuesday ... and not too long after, it was completely sold out.

The 21-year-old Filipino athlete has taken the sport by storm in 2026 ... and her popularity exploded after winning the Washington Open against Jessica Pegula in August.

Tickets to her matches have since become a hot commodity, with a ton of supporters wanting to catch her in action ... and the Toronto Open even added chicken adobo, a classic Filipino dish, to its concessions menu in her honor.

With all the hype, it was only a matter of time until she got her own product with the Swoosh ... and Eala was stoked to share the news with her 1.8 million followers on Instagram.

"I have my own shirt!!" Eala said with some mind-blown emojis. "You know what to do."

The fans understood the assignment ... 'cause shortly after the shirts went live, they were no longer available for purchase.

We assume Nike will restock the item soon ... but in the meantime, her U.S. Open kit is still available for now.

Safe to say tennis found its next big thing.