Portugal Colonial - Navarro and Pegula set up all-American Miami clash

Fernandez broke to take a 5-3 lead in the first set but Pegula responded perfectly, winning four straight games to take the set, bringing the crowd to their feet with a backhand winner down the line to clinch the set.

Both players struggled to hold serve in the second set, with the first seven games going against serve, but Pegula finally held to go 5-3 up and she held the final game to love to secure the win.

Pegula, the highest ranked American woman, will play against the rising star of USA women's tennis in Navarro who upset 12th seeded Italian Jasmine Paolini 6-2, 3-6, 6-0.

Paolini, who won the WTA 1000 Series event in Dubai earlier this year, faded after fighting back in the second set while Navarro confirmed her status as one of the most improved players on the tour.

With her 20th match win of the season, a record bettered only by world number one Iga Swiatek, Navarro is enjoying the most successful campaign of her career, having won her first WTA title in Hobart in January.

Pegula said the belief that comes from such a run of results will make her a difficult opponent.

"That feeling of winning a lot of matches, it's really tough to beat people like that and even if you do beat them it's never easy," she said.

"It will be a really good test for me to see where I'm at considering she is probably one of the hottest players on tour right now," she added.

The 20th seed's rise has impressed another of her compatriots, Coco Gauff.

"I'm not surprised by her being top 20, honestly. I would say (more) maybe how fast, it happened so fast. But when we played in juniors, she's always had an all-around game.

"She's a great athlete. She's a very smart player, she's giving the top players trouble. She's not somebody you want to see early in the tournament," Gauff said.

Gauff, the third seed, had little trouble in her routine 6-4 6-0 win over France's Oceane Dodin.

The American will face either Caroline Garcia or Naomi Osaka in the last-16.

J.Pereira--PC