The quarterfinal contests began at the U. S. Open on Tuesday, featuring several past champions and one highly anticipated sibling rivalry.

Serena holds off Venus to advance

Many anticipated a Serena-versus-Venus quarterfinal when the women’s draw was announced. And for the 27th time, it would happen. But this time the matchup had a unique caveat as Venus stood in the way of a potential historical feat for her sister. It is now well-known that Serena is seeking a calendar year Grand Slam, along with equaling Steffi Graf with 22 major titles. And after a highly competitive contest, she will continue on her path after a 6-2, 1-6, 6-3 win.

Any sign of early nerves were not apparent as both played high-quality tennis from the outset. Venus challenged the Serena serve with huge returns that drove her sister back, but she could not capitalize on the scoreboard. Meanwhile, Serena opened up break opportunities by attacking her sister’s second serve while mixing in drop shots with her big groundstrokes. She would gain the first break of the match at 3-2. Later, despite strong play from the 35-year-old, Serena would better her with some well-constructed points to gain a second break. She would serve out a first set that may have been her best of the tournament.

In the second set, Venus finally strung together enough successful points to place a Serena service game in jeopardy. Launching huge forehands, coupled with some suddenly nervous strokes by her sister, she broke serve and consolidated it at love to take a 4-1 lead. And after a few shaky games by the world No. 1, Venus would finish out the set strong.

However, in the third set, it was the younger Williams sister who gained an early break and then held off the 23rd seed after she earned a break point in the following game. Venus was forced to chase that break for the remainder of the match. Despite valiant efforts to do so, she could not find an equalizer, and Serena maintained her path toward history.

Asked about her feelings after defeating her sister, Serena stated, “It’s a really great moment. Venus is the toughest player I’ve ever played in my life and the best person I know. It’s going against your best friend and going against the greatest competitor in women’s tennis.”

She will advance to play Roberta Vinci in the semifinals.

Cilic holds off Tsonga comeback to advance

Two players who have spent much of the year attempting to fully return from injury met in the first men’s quarterfinal on Tuesday. Marin Cilic would hold off a big comeback to defeat Jo-Wilfried Tsonga 6-4, 6-4, 3-6, 6-7, 6-4 and take a key step towards defending his title, advancing to the semifinals.

In a first set where both players were frequently forced to fend off break points, it was the ninth seed finally breaking through to go up 5-4. Cilic would consolidate the service break and serve out a competitive set. Tsonga appeared to struggle with his movement and began to favor his leg late in the set.

The Frenchman did not look as sharp and as mobile in the second set, and he paid the price as the Croat gained an advantage. With his big serve as a weapon, Cilic held strong while finding just enough room to earn the one break he would need.

However, with the Flushing Meadows crowd lending their support, Tsonga received a boost in the third set. Despite some obvious difficulties with his left leg, he would find a late service break and managed to close out the set. The comeback was on.

In the fourth set, Tsonga suddenly appeared to move throughout the court with more ease once more and gained confidence. However, Cilic would ride his big serve to set up easier service games, while the Frenchman found more difficulty holding. This was evidenced when serving at 4-5, to stay in the match, Tsonga would find himself facing two match points at 15-40. He would fight back, taking four straight points to stay alive.

Fittingly, the set proceeded to a tiebreak, and it was Tsonga elevating his game once more. To the delight of the crowd, the 30-year-old evened the match, forcing a decisive fifth set. However, Cilic would take advantage of a poor service game midway through it, breaking at love. He would rely on his serve to close the match out, finishing with 29 aces.

Cilic addressed his ability to maintain poise during the comeback, noting “Even though I lost the third and fourth sets, I didn't back off my game plan. The atmosphere was electric. Jo came up with amazing shots.”

Vinci defeats Mladenovic for Berth in Semis

Prior to the Open, very few would have predicted that Roberta Vinci would advance to the semifinals, but that is exactly what happened after the first women’s quarterfinal. She would defeat Kristina Mladenovic 6-3, 5-7, 6-4.

The veteran was the more consistent player in the match, although the Frenchwoman showcased her potential in New York. The aggressive Mladenovic struck 51 winners but yielded 64 unforced errors in the match. She also struggled with her serve, placing just 47 percent of her first offerings in play and throwing in 11 double faults. Both players had multiple opportunities for service breaks, but the Italian was the more efficient with her opportunities.

The win marks Vinci’s first trip to a major semifinal at the age of 32. She was elated with her opportunity. “It’s an amazing moment for me. It's unbelievable,” she said. “The first semifinal in my career. I'm so happy. I don't have words to say.”