NEW HAVEN: Second-seeded South African Kevin Anderson locked up his sixth ATP quarterfinal berth of the season Wednesday with a straight-sets win over Jerzy Janowicz at Winston-Salem.

With the start of the US Open less than a week away, Anderson kept his campaign going at this hardcourt tune-up with a 7-6 (7/2), 6-4 victory over Poland’s Janowicz, runner-up last year to Czech Lukas Rosol.

“I was really pleased with today’s performance,” said Anderson, who fired 17 aces and saved all three break points he faced. “It was an improvement from yesterday. I served well today, which was the big goal. I took care of my own service games. When you’re playing a big server like Jerzy that’s one of the most important aspects.”

Anderson next faces 18-year-old Croatian Borna Coric, who needed only 57 minutes to rout Argentinian Diego Schwartzman 6-2, 6-1.

Coric, who toppled Andy Murray in his most recent hard-court quarterfinal in Dubai, will be seeking the fifth victory of his career against a top-20 player when he takes on Anderson.

In the other quarterfinal in the bottom half of the draw, sixth seed Thomaz Bellucci of Brazil meets Malek Jaziri.

Bellucci defeated Czech Jiri Vesely 6-1, 6-7 (7/9), 6-4, while Tunisia’s Jaziri downed Russian Teimuraz Gabashvili 7-5, 6-4.

The upsets continued in the top half of the draw as 13th-seeded American Steve Johnson dispatched third-seeded Frenchman Jo-Wilfried Tsonga 6-3, 4-6, 7-6 (7/4).

Johnson booked a meeting with Taiwan’s Lu Yen-Hsun, a 7-6 (7/1), 1-6, 7-5 winner over South Korea’s Chung Hyeon.

Pierre-Hugues Herbert kept the French flag flying, defeating Britain’s Aljaz Bedene 6-3, 6-0.

Bedene stunned top-seeded Frenchman Gilles Simon in the second round.

Herbert will take on Spain’s Pablo Carreno-Busta, who defeated Italian Simone Bolelli 6-4, 4-6, 6-1.

Wozniacki enters last eight

In New Haven, United States, four-time champion Caroline Wozniacki had to battle past Roberta Vinci Wednesday to book her quarterfinal berth at the WTA hardcourt tennis tournament in New Haven.

Denmark’s Wozniacki, seeded third this year in the US Open tune-up, saved three match points in the third-set tiebreaker en route to the 6-4, 6-7 (6/8), 7/6 (9/7) win, which saw her reach the quarter-finals for the seventh time in eight appearances on the courts at Yale University.

“I just kept fighting, really,” Wozniacki said. “It could have gone either way but thankfully it went my way,” she said.

Wozniacki next faces rising French star Caroline Garcia, who booked her quarterfinal spot on Tuesday with a win over Magdalena Rybarikova.

Defending champion and second seed Petra Kvitova of Czech Republic lined up a last-eight clash with seventh-seeded Pole Agnieszka Radwanska.

Kvitova rallied to defeat American Madison Keys 4-6, 6-1, 6-2, while Radwanska downed France’s Alize Cornet 6-4, 6-2.

Fifth-seeded Czech Karolina Pliskova survived a tough opening set to defeat Ukrainian Olga Savchuk 6-4, 6-1. She next faces Ukrainian Lesia Tsurenko, the lucky loser who replaced injured top seed Simona Halep in the draw and advanced with a second-round win over Barbora Strycova on Tuesday.

The remaining quarterfinal, set on Tuesday, will pit fourth-seeded Czech Lucie Safarova against Slovak Dominika Cibulkova.