Arantxa Rus, ranked 122nd in the WTA Rankings, was drawn against Carlota Martinez Cirez in New York, but had no trouble brushing the Spanish number 231 aside with a 6-4, 6-2 victory.
Rus took an early lead with a break in Martinez Cirez's first service game and proceeded to fend off four break points in her next two service games. With Rus breaking Martinez Cirez again to make it 5-1, the Spanish qualifier staged a comeback by fending off two set points and breaking Rus twice, thus setting the score at 5-4.
On her own service, however, Martinez Cirez was beaten by Rus for a third time as the latter took home the set.
Rus took her time distancing herself from Martinez Cirez in the second set, but after a break in the sixth game, Rus capped off the match with four consecutive won games as she won the set 6-2.
The Dutchwoman faces Briton Jodie Burrage, the 149th-ranked player, next at the US Open. The pair will face off on Wednesday.
De Jong fights past Gaubas
As Rus dealt with Martinez Cirez, Jesper de Jong eased his way past Lithuanian Vilius Gaubas with a 6-3, 6-4 victory.
De Jong, ranked 80th on the ATP Rankings, did not meet the deadline for the US Open and was thus forced to enter the qualifying tournament for the third year in a row. Against Gaubas, De Jong immediately dialled up the pressure and forced Gaubas to deal with nine break points. Gaubas, who got to break points just once, fended off nine of them, but had to concede the first set to the strong-serving Dutchman.
Gaubas started the second set disappointingly with a lost service game at the first go, but forced his first break point of the match to make it 2-1 and undo De Jong's first blow of the set.
The Dutchman, who made his first career ATP final in Bastad in July, could not break away from Gaubas until the tenth game, in which De Jong made the most of his only match point.
De Jong, the second seed in the qualifying tournament, is set to face Frenchman Harold Mayot next. The 152nd-ranked Mayot eliminated Englishman Johannus Monday on Monday with a 7-5, 6-4 win.