In truth, she looked tense, tight in the shoulders, unsure how to react, so kept it simple: She raised her arm for a single wave and went about the usual, calming business of preparing for the first match in a tournament.
Except, of course, this was not any first match nor any tournament.
It had been 14 years since Williams last trod this court. After winning her second title here in the California desert, she and sister Venus would turn their backs on Indian Wells after what they believed to be racially-motivated heckling at that 2001 final.
The decision would cost Williams many ranking points over the years, as well as the chance for more records in her already-packed history of achievements.
For no woman has yet won the Indian Wells title three times, and only two women have won both Indian Wells and Miami back-to-back: Kim Clijsters and Steffi Graf. Back when it all began for Williams, winning her first title here 17 years ago, aged just 17, she almost became the third to do the double, but lost in the Miami final—to sister Venus.
Now though, age 33, with 55 more titles since she last played at Indian Wells, including 18 of her 19 Grand Slams, and enjoying exactly two years unbroken at the top of the rankings, she will attempt to achieve both milestones.
Yet despite the fact that Williams has ‘been there and done that’ in so many places, this was a new experience: nerves, pressure and the unknown—she had never played the No68-ranked Monica Niculescu before.
So it was, then, that the former champion opened with a slew of errors and was broken to go 0-2 down. Niculescu, of all the unseeded women Williams could have faced, was perhaps the toughest she could have met to build a rhythm and a range. The Romanian uses huge amounts of slice and spin off the ground, and Williams could not settle.
But love from the Indian Wells crowd quickly kicked in again, and they cheered her on through a difficult first set, indeed a difficult match.
Williams survived seven deuces in the third game to fend off another break and then broke to level for 2-2. But Niculescu converted the second of her eight break points in the opening set to give herself the chance of serving it out at 5-4.
Williams, though, dug deep to break again, not once but twice, winning three straight games and the set, 7-5. But she had totted up 30 errors to 22 winners, and would barely hit half of her first serves into play during the whole match—a sign of tension if ever there was one.
And it showed once more in the second set, as Niculescu broke again in the first game. This time Williams broke straight back but could not do so again until the very end of the match, taking the set 7-5 after more than two hours of graft and determination.
She afterwards talked of her concerns about her reception when she arrived on court, and of the support that had helped her through this tough opener.
“I was a little nervous. The weeks leading up to it, days leading up to it, and eventually the hours, it was a little nerve-wracking. But now I’m good that I was able to do this. It definitely feels like one of the biggest and proudest moments of my career.
“It feels good; I was overwhelmed by everyone cheering. It was definitely worth it to come back and create new memories.”
She went on: “I don’t feel like I have to actually hold the trophy at the end of this. I feel like I’m already holding up a trophy. I have never felt that way before. I feel like being here is a huge win. Not only for me, but for so many people. It’s a wonderful feeling.”
She may not feel she needs to hold up the BNP Paribas Open trophy a week from now, but she is still most people’s favourite to do so. She next meets another player for the first time, No28 seed Zarina Diyas who, a year ago was ranked outside the top 100. Since then, the 21-year-old has scored a couple of top-20 wins—including Andrea Petkovic in Dubai—and reached the Osaka final.
In the fourth round there is then the prospect of a first meeting with Sloane Stephens since their three intriguing 2013 matches. The unseeded Stephens put out No13 seed Angelique Kerber and next plays Svetlana Kuznetsova.
Other seeds to fall were No17 Barbora Zahlavova Strycova, who lost to Anastasia Pavlyuchenkova, 6-3, 6-3, and No29 seed Camila Giorgi, who lost to Briton Heather Watson, 7-5, 7-5.
Both No3 seed Simona Halep and No7 Agnieszka Radwanska, remained on course for a quarter-final meeting, while No8 seed Ekaterina Makarova beat doubles partner Elena Vesnina, 6-4, 6-0. She next played No27 Timea Bacsinszky, and could face Williams in the quarter-finals.
MORE: The latest football news
MORE: The latest tennis news