It was the first occurrence since 1997, and because of it, a question that wasn't even a consideration before Monday now could haunt Serena Williams during the entire first week of Wimbledon.

Older sister Venus harkened to her glory days during the first round at the All England Lawn Tennis & Croquet Club with a stunning, 6-0, 6-0 victory over No. 36 Madison Brengle.

Defending Wimbledon champion Petra Kvitova says Serena Williams can with the calendar Grand Slam

The double-bagel was the first for Venus since she beat Chanda Rubin in 1997. Rubin was 21 years old at the time. Williams was 17 and playing her first professional match on grass.

Told about that love-love match 18 years ago, Venus asked, "Did I lose?" according to ESPNW. When told she won, Williams cracked, "I'm sure I enjoyed it.

Falling behind in early round Grand Slam matches helps Serena Williams?

The five-time Wimbledon champ had to enjoy her moment in the spotlight again, which have been few and far between since she was diagnosed with Sjogren's Syndrome, an autoimmune disease that saps her of her strength, in 2011.

Suddenly, Serena's march to her third Grand Slam title in 2015 has a potential menacing road block in the first week. If both keep winning, they are scheduled to meet in the fourth round. It would be the first time the sisters have met in a Grand Slam tournament since the 2009 Wimbledon final and the earliest the two have met in a Grand Slam event since the 2005 US Open, ESPNW reported.

Is Venus now Serena's biggest threat at Wimbledon?

"It would be great if I can continue to play well and get there," Venus said.

A Venus upset may not be as far-fetched as it seems. As Serena was losing to Alize Cornet in the third round of singles play last year, Venus also bowed out in the third round, but it was against eventual champion Petra Kvitova, and the score was 5-7, 7-6, 7-5.

Retired doubles specialist Rennae Stubbs is one observer who feels the elder Williams, seeded 16th in this year's event, has a legitimate chance to win Wimbledon.

"It was really the match of the tournament here last year against Kvitova, and nobody pushed Kvitova but Venus," Stubbs told The Guardian. "In that respect, I think Venus has an outside chance to win the tournament this year. Why not? If she's fit. She has Serena fourth round, but Serena is going to feel an unbelievable amount of pressure at this tournament. She feels it every tournament, but it's only building, and more by the time that match rolls around. And it's always hard for her against Venus."

Serena, coming off a 6-4, 6-1 win over qualifier Margarita Gasparyan in the first round, gave the answer anyone who knows her might expect about a possible match against Venus in the fourth round.

"I didn't know that," Serena said, according to the Los Angeles Times.

From now until the fourth-round match or until one of them is upset early, Serena likely will be reminded again. And again.