Mandlik was a game away from defeating Spaniard Paula Badosa on Wednesday before the second seed mounted a comeback to win 6-2 5-7 7-6(5).

Mandlik twice served for the second-round match in the third set but Badosa, a former world number two, broke both times before edging the deciding tiebreak.

Badosa said Mandlik did not play like the 240th ranked player in the world

"Looking at her ranking, she played an amazing match," Badosa said.

"I think sometimes it's a little bit confusing when you play against a player with her ranking because maybe you don't expect that kind of score and you think you're not doing things well.

"But to be honest, I think I played pretty good and she only played, unbelievable and I have to accept it."

Mandlik, whose mother won a French Open, US Open and two Australian Open titles, and twice reached the final of Wimbledon, has won three tournaments on the feeder circuit for the men's and women's tours this season.

The Florida resident arrived in San Jose unsure if she would even make the qualifying draw of the WTA 500 event and learned she had received a qualifying wildcard just 10 minutes before the draw.

Mandlik made the most of her opportunity, beating Swiss world number 94 Jil Teichmann and Mexican Fernanda Contreras Gomez, ranked 153rd, to make it to her first main draw on Tour.

Mandlik then defeated former world number 40 Alison Riske-Amritraj before almost pulling off an upset against Badosa.

Mandlik told the WTA earlier this week she had never been able to rub shoulders with top-level players before.

"To know that you can be there and be able to actually beat them, you create such a high belief in yourself and that you belong here," she added.