NEW YORK -- The image of Beyonce and Jay-Z courtside on the giant US Open video screens drew the expected cheers from the Arthur Ashe Stadium crowd Thursday night.
From the competitors on court, there were two reactions.
"I looked up and was like, 'Oh s---, Beyonce is watching,' " 87th-ranked Vania King said.
And from Serena Williams, who was the reason the superstar couple was there?
"Usually when people are there, I try to play better, especially if they're famous and they're doing so great at their job," she said. "It's like I want to show them that I'm good at my job, too -- minus today."
As hard as it might be to read Williams' changing moods on a tennis court, it is not difficult to distinguish between celebratory and chagrined.
And despite her 6-3, 6-3 second-round victory over King, Williams was definitely not thrilled.
"I just think it should have been a different scoreline for me," Williams said. "I feel like I made a lot of errors."
A qualifier into the main draw, King fondly remembers Arthur Ashe Court as the place where she sang "America the Beautiful" before one of Andre Agassi's final matches when she was a 17-year-old in 2006. That same year, she came through qualifying and reached the second round.
It was a considerably different memory than the only other time she played Williams, taking only one game off the world No. 1 in the second round of the 2014 US Open.
"I was disappointed I lost [Thursday], but I was happy at least that I got to show a little bit of my game," King said. "I felt like last time I played her, I got blown off the court and I was very, very nervous and wasn't able to impose any of my game because I was just overwhelmed by the situation."
This time she was overwhelmed only by Williams' serve.
"I felt like if I could get my racket on it, I was doing well," King said.
Williams followed a 6-3, 6-3 first-round win over Ekaterina Makarova, rich with carefully placed serves and blazing groundstrokes, with a match Thursday night in which she hit 13 aces and won 83 percent of her first serves while registering a stunning 38-4 advantage in winners.
Though Williams reported no residual soreness in the right shoulder that has severely limited her match play this year, averaging 107 mph on her first serves, she had 28 unforced errors to King's 11.
"[The shoulder] is stable," Williams said. "I've just got to keep it like that. It's two matches in, and usually you want to be able to play seven matches. It's not even close to the halfway point. I definitely want to keep it as good as it can be."
But the owner of the best serve in tennis knows what's most important to her if she is to surpass Steffi Graf for her 23rd career Grand Slam title.
"[The serve] was the best part of my game today," Williams said. "So seeing that's what I did the least [well] coming into this tournament, it's a really good sign [that I was] able to serve well and [I'll] hopefully gain momentum with that."
With the win, Williams hit still another milestone on her list, tying Martina Navratilova for the most Grand Slam match victories in the Open era at 306.
"Sometimes I don't even know that I'm hitting these milestones," Williams said. "But some of them, I'm really proud of. Like this one's kind of cool, to win 306. That's really a cool milestone."
Sister Venus Williams, who played earlier in the day on the covered Ashe Stadium court, defeating Julia Goerges 6-2, 6-3, made history of her own this week with a record 72nd Grand Slam main draw appearance.
At 36, Venus' goals are not unlike her sister's.
"I'm grateful that I can still play the game I want to play right now," Venus said. "As an athlete, as a tennis player, that's what you want. ... If you get to the point where you can't do that, that's where you need to start to think, 'OK, I need to move on.'
"I'm not at that point yet, and hopefully I'll be able to play the game I want to play right until the last day that I'm done."
For Serena, playing the game she wants generally accompanies winning tournaments. Even her opponents seem to expect nothing less.
"My coach asks me before each tournament, 'Who do you think is going to win the tournament?' And I'm like, 'Well, I'm still in the tournament,' " King said with a laugh. "But I always say 'Serena.' I mean, who else can you say? And you're always surprised if she loses.
"No matter what shape she's in, what condition, she's the best player in the world. ... If my coach asked me [now], I would say Serena. I've never not picked her."