Serena Williams is rolling in from Key Biscayne.

Venus Williams is back, too, but with a backache.

That the greatest sibling tandem in sports remains formidable is a modern tennis marvel. Catch the Charleston fan favorites while you have the chance.

“People gave the sisters a tough time for not playing more tournaments, but look at their longevity,” Family Circle Cup General Manager Bob Moran said. “How many players these days are playing to their level? And both are in their 30’s.”

The Family Circle Cup begins Monday on Daniel Island with defending champion Serena Williams ranked No. 1 and hoping to maintain momentum that includes Saturday’s 4-6, 6-3, 6-0 victory over Maria Sharapova in Miami’s Sony Open final.

Longevity is painful at times. Venus Williams, No. 18, had to withdraw from a third-round match in Miami against rising star Sloane Stephens. She hopes to recover from a lower back injury in time for a Family Circle Cup match Tuesday or Wednesday.

“That’s always a concern,” Venus said last in Miami when asked about lingering injury worries, “but I have dealt with injuries before in my whole career. I feel like also I know how to hopefully recover quickly from them.”

That would suit Lowcountry tennis enthusiasts. Most are aware that Serena owns 15 Grand Slam singles titles and Venus seven, and that the sisters have championed several South Carolina charities.

Venus got the home-crowd treatment when she won the 2004 Family Circle Cup title in 2004, and Serena bonded with stadium court fans on the way to titles in 2008 and last April.

Regardless of what happens on the court, there are a few off-court Venus Williams guarantees this year. She will participate in a Monday exhibition match with four Charleston women to showcase her EleVen apparel line (Althea Gibson Court, 4:30-6 p.m.) and will appear at Tour Tennis on Long Point Road in Mount Pleasant on Tuesday at 5 p.m. for a meet and greet session, another EleVen promotion.

‘An amazing dream’

The Family Circle Cup last year almost got that rarest of Williams treats, a sister vs. sister showdown. But Venus lost a three-set match to Samantha Stosur in the quarterfinals before Serena made short work of Stosur in the semis, winning 6-1, 6-1.

Venus is 32. Beyond common tennis ailments, she was diagnosed in 2011 with Sjogren’s syndrome, an incurable autoimmune disease.

Serena, 31, and has had back issues herself, notably in January during her quarterfinals loss to Stephens at the Australian Open when “it just totally locked up.”

“Oh, my gosh,” a frustrated Williams said after the Stephens match, “I’m almost relieved that it’s over because there’s only so much I felt I could do.”

The Williams sisters got collectively healthy enough last summer to win the doubles gold medal at the Olympics (Serena also won singles gold).

Winning in London was motivation at last year’s Family Circle Cup and at other tournaments before the Olympics.

“Every time I thought that I was getting close to losing, I would think about the Olympics literally and find a way to win the match,” Venus Williams said after claiming gold. “It was very close competition to get in here from the U.S. and get my ranking up enough. It was tough. But I’m here. It’s all I wanted. Just to arrive here was an amazing dream. To bring home a gold is just crazy.”

Venus and Serena also won the doubles gold medal in 2000 in Sydney and in 2008 in Beijing.

Sloane’s wall

Rio de Janeiro in 2016 is a possibility.

“With the doubles partner I have, absolutely,” Venus said. “But that’s what we want.

I think nowadays tennis players are seeing that you can play great tennis into your 30s. I think a lot of people were brainwashed early that you had to quit. It’s really not the way it is.”

Big sister still has it; Venus uncorked a 125 mph serve in a U.S. Open victory over fellow American Bethanie Mattek-Sands last year.

“The Williams sisters represent U.S. tennis right now, both on a women’s side and a men’s side,” Moran said. “They are inspiring the next generation which you can see coming into effect right now with Sloane Stephens. Sloane had their pictures on her wall when she was growing up. Now she’s a top 20 player at age 20. Sloane isn’t the only one, look at all the young Americans in the Top 100 right now. Youth today need to be inspired and they’ve certainly done that.”

Both Williams over the years seem to have gained an appreciation for tennis history and how they fit. Venus recently was asked about Stephens and comparisons to a young Serena.

“Well, I think Serena is an unbelievable player and a legend,” Venus said. “If anyone has the opportunity to be compared to her, it’s definitely a good sign.”

For now, the legend plays on, larger than life, with her nearly as legendary sister in tow.