Early in what would become a tight test of a U.S. Open final, Angelique Kerber sprinted forward to somehow reach a drop shot and scoop a down-the-line winner to a corner.

The Arthur Ashe Stadium crowd roared, and Kerber celebrated by raising her right hand and wagging her index finger in the air, as if to remind opponent Karolina Pliskova – and everyone else – "I'm No. 1!''

Yes, she is. And a two-time Grand Slam champion, too.

Kerber won her first U.S. Open title and the second major trophy of her out-of-nowhere breakthrough season, taking five of the last six games to beat a fading Pliskova 6-3, 4-6, 6-4 on Saturday.

Never a Grand Slam finalist before 2016, Kerber beat Williams for the Australian Open title in January, then lost to her in the Wimbledon final in July.

On Saturday, the No. 2-seeded Kerber trailed by a break at 3-1 in the third set before coming back against Pliskova, a 24-year-old Czech who was seeded 10th and hadn't been past the third round at a major until this tournament.

"For sure,'' Kerber told Pliskova during the trophy ceremony, "you have a great future.''

The present could not be brighter for the left-handed Kerber, the first woman from Germany to win the U.S. Open and to get to No. 1 since her idol and mentor, Steffi Graf.

It was Pliskova who guaranteed Kerber's ascension in the rankings by beating Williams in the semifinals, ending her record-tying 186-week stay at the top, which began in February 2013.

Kerber, who collected $3.5 million in prize money Saturday, lost to Pliskova the last time they met, just three weeks ago in the final of a hard-court tournament in Cincinnati.