On Monday at 8 a.m. ET, one of the most historic and awkward rivalries in sports is renewed when Serena and Venus Williams take the court in a fourth-round match at Wimbledon.

Appreciate this while you can. Even though the sisters have been hyped for nearly 20 years, their story still isn’t admired as it should be. Think of it: Two young girls, from an area not known for producing tennis talent, get into the sport because their father watched a match on television and decided to turn his daughters into the greatest tennis players in the world. And he succeeded. Monday’s match, and the 25 before them, are unprecedented in American sports history: in a major match at the most prestigious tournament in the world, two of the greatest athletes of their generation, who just happened to grow up in the same house, will face off. Here are 13 things to know before Venus vs. Serena XXVI.

1. The sister have played 25 times, with Serena holding a 14-11 advantage.

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Their first professional match was in 1998. They last played at the 2014 Rogers Cup. The matches, unfortunately, lack drama and aren’t the compelling theater you’d hoped for. Understandably, neither sister looks as if she wants to be there. Celebrations are muted. Although, in the past year or two, the back-and-forths have been a little bit more passionate than when they first started.

2. Serena holds a 7-5 record against Venus in Grand Slam matches.

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However, Venus holds a 3-1 record in major matches that aren’t played in finals and since this meeting comes in the fourth round, that’s theoretically an advantage for Venus. Of course, that 3-1 stat leads to this one:

3. Serena leads 6-2 in Grand Slam finals.

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Venus won once at Wimbledon and once at the U.S. Open, while Serena’s wins were divided between Wimbledon (three) and every other Slam (once each). Serena won the last time they played any match at a Slam, which came in the 2009 Wimbledon finals.

4. They’ve played five times at Wimbledon, the last four or which came in the final.

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Serena holds a 3-2 record in those meetings, winning three of the four finals but losing a semifinal in 2000.

5. Serena has also won five of last six meetings overall.

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But Venus won the last one — a 6-7 (2), 6-2, 6-3 victory last year in Montreal when Serena was in the midst of a dominant 61-4 run that continues through this weekend.

6. The sisters have played only two matches before a tournament quarterfinal. This is the third.

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Their first match was a second rounder at the 1998 Australian Open. Seven years later, they played in the fourth round at the U.S. Open. Venus won both of those meetings. Every other match has been either a quarter (three), semi (seven) or final (11). There have also been two round-robin meetings at the year-end WTA championships.

7. The sisters have combined to win 27 of the last 62 Grand Slams in which at least one of them has started.

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That’s a winning percentage of 44%. So, since the century began, if a Grand Slam was played with at least one Williams sister in the draw, the odds are almost 50/50 that she’d win.

8. Since 1999, the only years in which a Williams sister hasn’t won a Slam are 2004, 2006 and 2011.

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In 2004, Serena was shocked in the Wimbledon final by a 17-year-old Maria Sharapova. In 2011, Serena lost her cool and the U.S. Open final to Sam Stosur.

9. The longest winning streak in the series were six straight for Serena from 2002 French Open to 2003 Wimbledon.

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Serena was threatening to tie that record last year before Venus got the best of her in their last match.

10. Ten of the 25 matches have gone to three sets.

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Five of those have happened in the last 11 meetings, after Richard Williams stopped rigging the matches, of course. (Kidding.)

11. In 2002, the Williams sisters alternated between No. 1 and No. 2.

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In Venus’s third stint at No. 1 — all of which came during 2002 — she was one spot ahead of her sister, who was at a career high of No. 2. Two sisters, atop the tennis world officially. Then, when Serena won Wimbledon, the sisters flip-flopped with Serena taking over the top spot and Venus slipping to No. 2.

Yet for all her Grand Slam wins, Venus has only been ranked No. 1 for 11 weeks, a full year less than Caroline Wozniacki who, of course, has zero majors. In fact, of the 21 women to get the No. 1 ranking since they began in 1975, Venus has the second-shortest reign. Only Evonne Goolagong Cawley, the second woman to be No. 1, had a shorter time at the top, just two weeks.

12. Venus is the only player to defeat Serena on grass two times, while Serena is the only player to defeat Venus on grass more than two times.

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That’s what happens when the sisters are a combined 167-28 on the surface.

13. Serena is a heavy favorite to win on Monday.

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British books are giving Serena 1/4 odds to beat her sister, who is getting 4/1 odds on the flip. Those are the same exact odds Stan Wawrinka (1/4) is getting to beat David Goffin (4/1). I don’t know though. I like Venus in this one. The pressure of the Grand Slam, not to mention the continued oddity of facing off against her big sister, might be too much for Serena, especially as this year represents Venus’s last real shot to win once more at the All England Club.

Prediction: Venus in straight sets