Serena Williams To Face Sister Venus In U.S. Open Quarterfinals

Serena Williams will face a formidable opponent Tuesday when she continues her quest for a sixth U.S. Open title: her own sister, Venus Williams.

Following a decisive victory Sunday against 19th-seeded Madison Keys, according to MSN, Serena has set her eyes on history. If she wins the 2015 U.S. Open -- her third consecutive U.S. Open victory -- Serena will become the first woman to win a calendar-year Grand Slam since Steffi Graf did it in 1988.

On Sunday, when a reporter asked why it's been so long since a woman won the Grand Slam, Williams answered in true Serena fashion.

"I don't know why it took me so long."

Unfortunately, Serena's road to the history books leads through danger: her own sister, Venus Williams. Thanks to the way this year's U.S. Open has shaken out on the women's side, Serena and Venus will face each other in the quarterfinals Tuesday. The winner will move on, the loser will go home.

The irony of the situation is not lost on New York Daily News tennis writer Flip Bondy. On the one hand, Venus Williams is no-doubt pulling for her sister to make women's tennis history. On the other hand, she's a fierce competitor who won't take a match with her sister lying down; but if she beats her sister, she denies her the chance at the coveted Grand Slam.

The two women have faced each other in official competition 26 times in their combined careers. Serena leads the in-family competition 15-11.

To the fans, says Bondy, a Serena-Venus matchup makes for good tennis and a good story, but it's also somewhat awkward.

"These matches always provide astounding pace and points, but they also leave us all feeling a bit uncomfortable, like intruders at the family dinner table."

In fact, the situation is so awkward, and the stakes so high, that Venus and Serena's mother, Oracene Price, can't bear to watch (at least in person); she's on the record as saying she won't attend the match.

At 35, Venus Williams is no longer one of the top 10 women's tennis players in the world, according to ABC Sports. Still, that doesn't mean that Serena is expecting an easy match. In fact, she says, she considers her sister her equal.

"It's like playing a mirror."

Serena Williams and Venus Williams will face each other in the U.S. Open quarterfinal on Tuesday at 7 p.m. Eastern Time.

[Image courtesy of: Getty Images/Chris Trotman]