Last year, an abundance of victories at the Sony Open prevented Agnieszka Radwanska of Poland from doing what she adores almost as much as tennis, even with a $712,000 check in her grasp.

This time around, the bubbly defending champion purposely got in her shopping at Sawgrass Mills with her Sony-playing sister Urszula a couple of days before the tournament started — then disposed of her opening-match opponent Thursday in a little more than an hour.

Plantation native Sloane Stephens, who turned 20 on Wednesday and said she “was asleep” during her ugly first set Thursday, woke up quickly to survive another day.

And the Williams sisters — World No. 1 Serena in the day and No. 18 Venus at night — won in their initial matches, though Venus needed three sets and a tiebreaker to do it.

“I will do everything, you know, to hold the trophy again,” said fourth-ranked Agnieszka, nicknamed Aga, who defeated No. 38 Hsieh Su-Wei 6-3, 6-2 on Thursday, and won the biggest title of her career by upsetting No. 2 Maria Sharapova at last year’s Sony. “It’s a great place to play tennis. When you come here you can see that the people here love tennis. It’s always great weather.

“Winning this kind of tournament, it’s almost like winning Grand Slam. … Definitely great memories.”

Radwanska, 24, studies tourism at the Polish Sport University in Krakow in what spare time she can afford. Her favorite actress is Nicole Kidman. Her favorite musicians are Green Day, Black Eyed Peas and Eminem. Her favorite city is Paris. Her favorite mall is Sawgrass Mills. And her favorite purchase: handbags.

“Sawgrass outlet is huge,” she said. “Everything is there. Yeah, is for sure like half-day trip or even all day long. … I bought a couple of things and also a couple presents for my parents. Some shoes, boots.

“I have to win this tournament to buy a nice handbag.”

If so, she’ll bring her younger sister, nicknamed Ula, who is ranked 33rd and won her first match Wednesday. The younger Radwanska meets No. 17 Ana Ivanovic in the final day-session singles match Friday on Court 1.

“There is no jealousy between us,” Radwanska said when asked if it’s tough for Ula to constantly trail Aga in the rankings. “We always support each other, always stay on the same side. Our whole life is about tennis, so when we’re together, we’re talking about everything except tennis.”

After torrential rain delayed Wednesday’s evening matches by nearly an hour, the sun and the tennis stars (mostly female) emerged en masse Thursday on a glorious day in Key Biscayne. Meager day crowds basked under pastel-blue skies, temperatures in the mid 70s, humidity under 40 percent and steady breezes.

The top-ranked men, led by No. 1 Novak Djokovic, emerge Friday. Djokovic meets Lukas Rosol of the Czech Republic at 8 p.m. World No. 2 Roger Federer and No. 4 Rafael Nadal do not play this week.

“It’s good when they get excited and they’re cheering a lot,” Stephens said of the vocal fans. “I think they are as exhausted as I am, being out there in the sun and cheering.’’

Stephens — the Sony Open’s top-ranked American woman after Serena Williams — played some of her school-age years at Plantation Central Park. And though she lists her home as Coral Springs, she spends much of her time these days in the Los Angeles area.

Stephens trailed 0-6 after one set to Olga Govortsova of Belarus, but won 0-6, 6-4, 6-4.

“I definitely just needed to wake up and start playing,” said Stephens, who defeated Serena Williams two months ago in an Australian Open quarterfinal and will play Venus for the first time on Saturday. “A lot of battling and just hanging in there.”

Serena, who double-faulted to open her match and made it somewhat interesting for a minute or two by trailing 0-40 in that first game, dominated Flavia Pennetta of Italy for a 6-1, 6-1 victory.

“My attitude is, it always feels better when you’re No. 1,” said Williams, a five-time Key Biscayne winner. “I missed a few shots, but only because … I was off footwork-wise. But it’s always good just to win a match and stay in the tournament and keep going.”

Venus later struggled to defeat Kimiko Date-Krumm, at 42 the oldest woman on tour, 7-6 (7-3), 3-6, 6-4, in the most exciting high-profile match of the day. Date-Krumm saved six match points before Williams’ victory.

In other play, world No. 11 Marion Bartoli of France retired from her match against Andrea Petkovic with an injured left foot.