Power tennis was on full display in Arthur Ashe Stadium on Wednesday night as Venus Williams squared off against Petra Kvitova while Kevin Anderson faced Sam Querrey in the quarterfinals of the US Open.

In a match that had the feel of a final, Williams defeated Kvitova 6-3, 3-6, 7-6 to advance to the semifinals. It was high-intensity tennis from the beginning as each player exhibited their strength, pounding the ball from the baseline.

In the first set, Kvitova was big out of the starting gates, gaining the first break of serve to go to 3-1. But the American, playing with confidence, began to attack more freely and she forced the 13-seed into 16 unforced errors as she did not drop another game in the set, winning 5 straight.

The script flipped in the second as the Czech began to dictate play and gained momentum. Nevertheless, Williams had a look at five break opportunities but could not cash as many of Kvitová’s 16 winners came during high-pressure points. Meanwhile, the Czech capitalized on her one break opportunity and equaled the match by taking the set.

Play heated up in the third set as the intensity rose even higher and much of the crowd hung on each point. Kvitova appeared to ride the momentum of the second set into the third as she gained a 3-1 lead, with an early service break. But the 37-year old battled back with a break of her own to even the set at 3-3. Both players were strong on their serve the remainder of the set as neither could sniff a break opportunity. Appropriately, the match would be determined in a tiebreak.

There, Williams put the match in a stranglehold as she was stronger in the big moments and more consistent.  She raced out to a 6-1 lead before double-faulting but closed it out at 7-2 as the two titans finally put down their weapons.

“I'm so fortunate to have won that match. It came down to the wire,” Williams said. “I try to tell myself enjoy the competition, enjoy the battle and I think I was able to do that.”

Venus will advance to the US Open semifinals for the first time since 2010 and will face Sloane Stephens who advanced on Tuesday.

The loss ended an incredible run by Kvitova who missed months after she was attacked by a knife-wielding intruder, who caused severe injuries to her hand last December.

Later, it was Anderson advancing to his first grand slam semifinal with a 7-6 (7-5) 6-7 (9-11) 6-3 7-6 (9-7) win over Querrey.

The nightcap featured first-strike tennis as Anderson and Querrey attacked with big shots. Rallies were few and far between as the two big-hitters dominated service games in the first set. Not surprisingly, with the two combining for 17 aces, as they consistently bombed serves bigger than 130 mph, the set went to a tiebreak.

Each player continued their serving exhibition in the tiebreak but a double fault opened the door for Querrey who gained the advantage. However, Anderson came up with 2 massive returns to turn the tiebreak in his favor and he closed out the first set.

In the second set, Anderson began to make inroads into the Querrey serve as he pushed him in the opening game, earning two break opportunities. The American fought them off but was not as successful in the 5th game where Anderson took the first service break of the match. But for the first time in the match, Querrey began to pump himself up and the New York crowd fed off of it. He would quickly break back to even the set and once again a tiebreak would ensue.

Querrey set the trend in the opening point of the tiebreak with a massive winner and followed that with a mixture of good defense while picking his opportunities to take big shots. With Anderson looking rattled, Querrey ran out to a 6-1 advantage. However, Anderson quickly turned the tiebreak around by saving 5 set points to even the breaker at 6-6.

In an epic point, Querrey played tremendous defense with Anderson at the net attempting to put the point away with overheads, and after a few opportunities, the South African missed a put-away. Anderson would recover and the tiebreak went back and forth with each player strong on serve. But after Querrey gained a mini-break to go to 10-9, Anderson sent a second-serve return from Querrey long and the match was evened up.

In the third set, Anderson came out shaky but quickly regrouped and Querrey lost some control on his own service games. Anderson took full advantage as he ran through the set, winning 6-3.

The two sluggers continued their big-hitting in the fourth set, which was decided by a tiebreak, again. But it was the aggressive play of Anderson who gained the advantage, striking massive shots, particularly from his forehand wing. He would close out the match, playing more clean and aggressive in the key points. The 31-year old ripped 67 winners in the match to Querrey’s 44 and fired 22 aces. He was outwardly fired-up throughout the match, something many have not seen from him in the past.

“I've put in a lot of work so it feels good that I reached a milestone that I haven't before,” said Anderson afterward. “That was one of my goals, to try to further my previous best result, and I was able to do that today. It feels very good. I want to say it's a fantastic feeling, but I'm still in this tournament. I am going to have another opportunity to go one step further.”

Anderson will meet Pablo Carreno Busta in the semifinals.