Key Biscayne, Florida: Basking in her latest victory, a beaming Venus Williams stood near her changeover chair launching autographed balls into the stands, steering her shots with body English and applauding the fans who scrambled for the souvenirs.
For Williams, tennis is still fun. She's 34 but on the rise in the rankings, and she beat former No. 1 Caroline Wozniacki 6-3, 7-6 (1) Monday to reach the Miami Open quarterfinals.
Williams is a three-time Key Biscayne champion, but her most recent title came in 2001. Seeded 16th, she's into the quarterfinals at the tournament for the first time since 2012.
"Tennis has always been a blast," Williams said. "But, you know, I'm feeling good out there."
She could meet her sister Serena in the final. Serena, who has won the tournament a record seven times, advanced by beating 2006 champion Svetlana Kuznetsova 6-2, 6-3.
American Sloane Stephens made it to the final eight at Key Biscayne for the first time by beating 18-year-old Belinda Bencic 6-4, 7-6 (5).
In men's third-round play, four-time champion Novak Djokovic defeated qualifier Steve Darcis 6-0, 7-5 and will next face Alexandr Dolgopolov. No. 4 Kei Nishikori and No. 5 Milos Raonic also won.
No. 22 John Isner, the lone remaining American in the men's draw, defeated No. 9 Grigor Dimitrov 7-6 (2), 6-2.
While Serena Williams, 33, has been ranked No. 1 for the past two years, Venus' fortunes are only lately on the upswing after health issues caused a long slump that stirred retirement speculation.
In January at the Australian Open, she reached her first Grand Slam quarterfinal in five years before losing, and with the victory over Wozniacki, she's 4-0 in 2015 against top-10 players.
Venus skipped Indian Wells, where Serena recently ended a 14-year family boycott after being booed there as a teenager. Venus said it was wonderful to see the warm reception her sister received there this month, but was noncommittal regarding whether she'll return.
Given the way she's playing lately, she might have several chances. Williams credits her persistence and optimistic nature for her recent resurgence, which comes more than three years after she was diagnosed with an autoimmune disease that can cause joint pain and sap energy.
"I don't give up, and I believe in myself no matter what the odds are and what you may experience," she said. "I have always seen it as something to overcome, and not something that could stop me."
Unlike her sister, she has never tired of tennis, a problem for some top players even before their skills decline.
"I never get bored, actually," Venus said. "Tennis is definitely not pushing paper. I mean, when you get out there you have no idea what's going to happen in the point. You can try to plan it the best you can, but it's all up in the air. You have to improvise every single time. That never gets boring."
Williams won Monday with her familiar high-wire approach, swinging aggressively from the baseline. Sometimes she missed badly, but she hit 40 winners to nine for Wozniacki.
"Today I played similar to how young V would have played, either knocking a winner or knocking an error," she said, with a grin. "It's fun to just hit out, though. It feels good."
She moved forward more often than in the past, winning 14 points at the net, and used her long strides to chase down balls in the corners and extend rallies.
The stadium crowd applauded Williams' staying power. So did the 21-year-old Stephens, who could face her in the final.
"She is a superhuman," Stephens said. " I don't know how she does it."
"She just has so much belief in herself and her ability," said U.S. Fed Cup captain Mary Joe Fernandez, an analyst for ESPN. "It is a great story for sure."
Key Biscayne has always ranked among Williams' favorite tournaments, because she lives 90 minutes up I-95 in Palm Beach Gardens. She's playing in the event for the 16th time, which leaves lots of room for reminiscing.
"My first match here, there was a rat in the stands," she said, with a laugh. "They had to stop the match. That was intense."
She enjoys looking back, and also looking ahead. She'll face Carla Suarez Navarro on Tuesday night for a berth in the semifinals.