By Chris Oddo | Sunday September 4, 2016

Angelique Kerber stayed red-hot at the U.S Open and kept up the pursuit of the No. 1 ranking by defeating Petra Kvitova, 6-3, 7-5 in Sunday’s first night match on Arthur Ashe Stadium.

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The German’s victory means that Serena Williams needs to reach the final in order to maintain the No. 1 ranking next week.

Williams has held the WTA’s top spot for 186 weeks consecutively, tying Steffi Graf’s all-time record, but Kerber has been relentless this summer and keeps knocking on the door. Two weeks ago in Cincinnati, Kerber was one match from overtaking Williams in the rankings but she fell in the final to Karolina Pliskova.

This week in New York, Kerber has dropped just 18 games in four matches, but her takedown of two-time Grand Slam champion Kvitova in the pair’s first meeting at a major has been her most impressive effort.

"I knew that I had to play my best tennis tonight," said Kerber. "Petra's a great player."

Kerber was stingy from the baseline, striking eight winners against eight unforced errors, and she was tough on the Czech’s second serve, winning 22 of 31 points against it.

Kvitova came in with rising confidence but was unable to hit her spots often enough in the 87-minute contest. She committed 43 unforced errors and 32 winners.

After dropping the first set in 31 minutes, Kvitova came out determined in the second set, but Kerber’s smothering defense and patient, tactically sound approach eventually wore the No. 14 seed down. The German broke in the final game when Kvitova tossed in her seventh double-fault on match point.

Kerber improves to 5-4 lifetime against Kvitova and moves on to face No. 7-seeded Roberta Vinci in the quarterfinals.