WHAT HAPPENED: CoCo Vandeweghe and Karolina Pliskova played a tennis match on Wednesday and a heavyweight bout broke out.

Two of the game's heaviest hitters planted their feet squarely on the baseline and then proceeded to unload sledgehammer serves and bruising roundhouse forehands at each other without let-up, until Vandeweghe was the one left standing with a 7-6, 6-3 victory and the American's first-ever spot in the US Open semifinals.

The 20th-seeded Vandeweghe is the third American into the semifinals, joining No. 9 Venus Williams and unseeded Sloane Stephens. Madison Keys will look to make it a clean sweep for the U.S. when the No. 15 seed plays Kaia Kanepi of Estonia on the evening program.

"Let's make it four for four," Vandeweghe told the fans.

Related: CoCo Vandeweghe, the Q&A

The last time there were four Americans in the US Open semifinals was in 1981, when Tracy Austin, Chris Evert, Martina Navratilova and Barbara Potter all advanced.

For the hometown girl who was born and lived in New York until she was about 8 years old, the magnitude of the moment was one to cherish. Vandeweghe dropped to her knees after Pliskova could not return a 103 mph serve on the second match point. Then Vandeweghe made a quick quick run over to the players box to exchange handshake with her coach Pat Cash, the former Wiumbledon champion who took over coaching duties in June.

Ever since winning the 2008 US Open girls' singles title, Vandeweghe told the crowd she had been thinking of a moment like this.

"I always dreamed of being on the real big stage," said Vandeweghe, 25. " I couldn't wish for anything more."

The defeat was a double body blow to the top-seeded Pliskova. The 25-year-old made her only career Grand Slam final at last year's US Open and needed to reach the final again to extend her eight-week reign atop the rankings ladder. With the defeat, she will lose her No. 1 world ranking to Spain's Garbiñe Muguruza when the new rankings come out at the conclusion of the tournament

This was not tennis for the faint of heart nor if you were looking for finesse. This was a 94-minute slugfest with no quarter given or taken. The power of their shots reverberted off the closed Arthur Ashe stadium roof on a wet afternoon.

play video Cognitive Highlight: CoCo Vandeweghe - Quarterfinal

While full of drama and tension, the match was not played at a particularly high standard. Vandeweghe committed 32 errors and five double faults. Pliskova had 21 errors. Both players had to come off the ropes to remain in the fight.

In the opening set, Pliskova fought back after dropping her serve in the third game to break back to even the set at 4-4. Pliskova then held for 5-4.

It was now Vandeweghe's turn to stiffened when she fought off a set point in the next game with a strong backhand.

In the tiebreak, Vandeweghe went up 3-0 and then had to hold on, taking the set on her service winner for 7-4. The usually unflappable Pliskova slammed her racquet on the court in disgust.

Vandeweghe again went up early in the final set 3-1 but dropped her serve for 3-2. This time the American roared back to break again for 4-2 lead.

Pliskova was not down and out yet. In the last game she had one break point. She saved a first match point before being overpowered on a big serve on the second match point.

 

WHAT IT MEANS: Vandeweghe is assured of reaching a career high in the world rankings of at least No. 15 at the end of the tournament and can still cliimb higher if she reaches the final.

For American tennis, if Keys can make it four for four in the semifinals, it will secure the first all-American semifinal since 1981 and assure the first all-American women's final since 2002, when Serena Williams beat sister Venus.

MATCH POINT: This match had the feel of a final, but Vandeweghe still has two more rounds to claim her first Grand Slam crown. Is she ready to hoist her first major trophy?