If tennis' broadcasters were hoping for emotional scenes of tears from teenager Alexandra Eala after she secured one of the biggest upsets of the WTA season they were left disappointed.

But the final point, as she broke the serve of world No 2 Iga Swiatek, for the eighth time, revealed much more about the young Filipina than any waterworks would have.

The big-hitting 19-year-old showed no signs of being intimidated playing against one of her idols, and was, instead, a picture of poise, as she dismantled Swiatek's serve early on to grab control of the match — and never looked like relinquishing it thereafter.

"I don't know what to say," Eala said in her on-court interview. "I mean, I'm just in complete disbelief right now, and I am on cloud nine.

"It's forever in my heart."

Eala's face quivered, on the edge of tears, as she began to process the magnitude of her victory, which sent her into the semifinals of the Miami Open, but she kept her emotions in check, composed herself and celebrated in a controlled manner, before calmly and diligently undertaking her post-match duties.

"I think I was so in the moment, and I made it a point to be in the moment on every point, that it's hard to realize what just happened. It's hard to realize that you won the match," she explained, when asked about her immediate emotions after beating the five-time major winner.

"I really tried to soak it all in, because this has never happened to me before, and that's why I was looking at the screen. You know, I really wanted to keep that moment in my mind," she added.

In the biggest game of her WTA Tour career to date, Eala played with a poise that belied her inexperience, but underscored an impressive level of preparation for such a moment.

"I don't have a lot of experience on the WTA Tour, that's for sure, but I do have experience with compartmentalizing. I have experience with being professional," she said.

"I have no hesitation in bringing that part of me out when I'm on court, and when I'm in a setting that calls for professionalism," she added.