In the meantime, no one else has stepped up to even join the conversation, a void that has left the argument -- so who's really No. 1? -- to fester for months now. We could get the definitive answer on Saturday night.
Williams versus Wozniacki. Finally.
Since Williams returned before Wimbledon to begin her seemingly inexorable climb back to No. 1, fans have been hoping for a Serena-Wozniacki showdown. The most anticipated women's match of the summer will take place in the semifinals of the U.S. Open at Arthur Ashe Stadium, and the match, quite frankly, holds more intrigue than the final will -- no matter who makes it there. In the other semifinal, Samantha Stosur (the ninth seed and 2010 French Open finalist) takes on surprise semifinalist Angelique Kerber of Germany (unseeded and ranked No. 92). Stosur is the first Australian woman to make the U.S. Open semifinals since Wendy Turnbull in 1984 -- the year Stosur was born.
For her part, Wozniacki, 21, bristles at the criticism and the allusions to the import of her match with Williams, 29, a three-time U.S. Open champion. Wozniacki is quick to defend her record, including six tournament victories this season that have kept her at No. 1 for 47 weeks now.
"To be honest, I don't care," Wozniacki said after beating No. 10 Andrea Petkovic in the quarterfinals, when asked if the match with Williams would answer questions about her game. "I don't care what people think and say or do. I care about what I know best. I go out there, and what I care about is that I give 100 percent every time. You win a match, you lose a match sometimes. It's sports. I know I'm going out there and playing a great champion. She hasn't won 13 Grand Slams for nothing. She's been out there on the big stage many times.
"I'm No. 1 in the world at the moment, and I've been playing well and I have had a great year. You know, both have nothing to lose. We'll just go out there and hopefully [it] will be a good battle. That's all that matters, you know, that I give it my all. After the match, we'll see how good that was."
Williams owns a 2-0 record against Wozniacki, both matches coming in 2009. The two met early that year in an Australian Open warm-up in Sydney, with Williams pulling out a tough 6-7 (5), 6-3, 7-6 (3) win when she was ranked No. 2 and Wozniacki was No. 12. They played again late in 2009 at the WTA Championships in Doha, Qatar, with Wozniacki retiring, down a set, with an injury.
Asked about Wozniacki, Williams was complimentary. Then again, Williams isn't about to argue her case for No. 1 in the media.
"I think Caroline is a very consistent player," Williams said after beating Anastasia Pavlyuchenkova in Thursday's quarterfinals. "Consistent on the court and then consistent in playing tournaments and doing well and winning tournaments, as well as going really far in tournaments. That's pretty much what it takes to be the best.
"I think her weapon is the fact she never gives up. ... That's probably the biggest weapon I think you can have in all of tennis. Also, she's moving really fast. She's running every ball down. That's a great weapon to have, as well.''
Still, it is a foregone conclusion by some that Williams, with her powerful serve, has too many weapons for the steady if unspectacular game of Wozniacki. But not everyone is writing off this semifinal as an automatic victory for Serena.
"I saw [Williams'] match against Anastasia today, and I think if Caroline plays really well and if she changes up the rhythm and plays as consistent as she is always, she definitely has chances,'' Petkovic said. "I think Caroline is one of the most underestimated players out there, because you have to win each and every point against her. If you don't do it, you lose.
"If Serena plays well, it's tough to beat her. Anybody can -- will lose against her if she's on fire. But if Serena struggles a little bit and Caroline plays consistent, she definitely has her chances."
As for Wozniacki, she is not shying away from this confrontation. On the contrary, she seems to welcome it. Maybe Wozniacki wants to finally answer the question that she hates to hear, too.
"I feel I always play best when there's something big, when something big is going on," Wozniacki. "This is what you practice for. This is what you want. You don't want to play on practice court 15 or out on the small courts. You want to play in here. You want to play in front of a full crowd. I'm excited about that."
No matter what happens Saturday night, Wozniacki is already assured she will walk away from the U.S. Open with her No. 1 ranking intact. Williams could rise only as high as No. 12 if she wins, per the points system used by the WTA. But if Williams captures her 14th Grand Slam title, the ranking points will be largely irrelevant to the argument.
We'll all know who really is No. 1.