MELBOURNE, Australia -- Serena Williams has plenty of experience being the younger one. But in her Australian Open quarterfinal against Sloane Stephens, she'll get to be the older one for a change.
Stephens, of course, isn't a sibling of Serena's, like older sister and fellow Grand Slam champion Venus. She isn't even a protege, really.
"I feel no responsibility," Serena said. "I doubt she has any expectations of me to be responsible for anything. It's hard to be a real mentor when you're still in competition."
Even in the absence of a tangible bond, there are still enough connections between the two to make this meeting of generations seem meaningful. Both the 31-year-old Serena and the 19-year-old Stephens have outgoing, fearless personalities and penchants for mischievous remarks. Both possess powerful, speedy games with big serves while standing under 5-foot-9 -- barely mid-height for a female pro tennis player.
The off-court similarities help explain why they quickly became friends since Serena spotted the American teen in the locker room at a World TeamTennis event four years ago. And now, with Stephens' results improving quickly, they're also starting to cross paths on the court.
Their first meeting came three weeks ago in Brisbane, where Stephens provided some resistance during Serena's 6-4, 6-3 win. During the match, Stephens also appeared to tell her coach that Serena's fist-pumping was "disrespectful," though she has downplayed the comment since.
Now they will play at a major for the first time, though it's hardly anticipated as a changing of the guard. Serena looks very much in her prime and will be playing in her 35th Grand Slam quarterfinal, while Stephens will be making her first appearance at this stage. Even in relative terms, there is no comparison. Serena won her first Grand Slam at 19, whereas Stephens, playing in a generation that peaks much later, is merely the last teenager left standing at this event.
Stephens, who grew up admiring Serena, Venus and Kim Clijsters, will do her best to forget who is on the other side of the net. She's trying to think of it as the "quarters of a Grand Slam" which "just happens to be Serena."
Having played the 15-time Grand Slam champion recently will help with that.
"It will feel more of like a regular match instead of all the other things to think about," she said.
Stephens also has had a tougher road to the quarterfinals, going through a trail of fellow up-and-comers that included a battle against Bojana Jovanovski in the previous round. She also played two straight weeks before the Australian Open to get in match practice after missing the fall to rest an injury, and she reports no aches and pains.
Serena suffered an ankle injury earlier in the tournament, and while it hasn't affected her results, it appeared she did have some problems during a doubles match Tuesday.
Her biggest strength has been her serve, which has improved with age. She has twice hit 128 mph during this tournament, her fastest ever, and in the fourth round her first-serve percentage was an incredible 87 percent. Stephens is no slouch in this category -- she hit one at 120 mph last week -- but does not get nearly as many free points. It's another sign of the gap between the two.
In this match, at least, it appears Serena is going to like the experience of being the older one.
Prediction: Serena in two sets
Victoria Azarenka (1) vs. Svetlana Kuznetsova: Azarenka's presence at this stage isn't a surprise, but Kuznetsova's resurgence is somewhat unexpected. Just before the season began, the two-time Grand Slam champ talked about being fresh and eager to go after some forced time off because of a knee injury, yet even she didn't expect that her renewed enthusiasm would yield such good results so early.
"I went to Thailand, I went to Bali, on the beach with crutches, all day long, and I had blisters on my hands," she said. "But anyway, I had time home to just refresh my mind, and then I just understood that I want to play this game."
After struggling against Jamie Hampton, Azarenka resumed cruise control in her last match. Kuznetsova's heavy game could be another challenge.
"I know I got the game to give her some problems," Kuznetsova said, "and I will just do my best and just try to enjoy it."
But the Russian is still working her way back and concedes that her fitness isn't 100 percent. Azarenka is likely to be the more composed and consistent of the two through the match, and that could make the difference. If so, it'll show again how far the once combustible No. 1 has come in the past year.
Prediction: Azarenka in three sets
Jo-Wilfried Tsonga (7) vs. Roger Federer (2): Federer has come through a potentially tough draw very efficiently, and now a familiar threat awaits. Though the Swiss leads the head-to-head 8-3 and has won their past four encounters, the memory of Tsonga's two-sets-down comeback at Wimbledon in 2011 lingers as a reminder that the Frenchman can blow through anyone at any stage if his game catches fire. And he has some history in Australia, having produced a rare pounding of Rafael Nadal on his way to the final in 2009.
But Tsonga hasn't been on fire so far, even though the injury worries that followed him into this event haven't materialized. Federer has looked sharp, so based on current form, he'll be the favorite.
Tsonga has been talking about the contagious enthusiasm of his new Aussie coach, Roger Rasheed, so he should at least have a positive attitude going into the match.
Prediction: Federer in four sets
Jeremy Chardy vs. Andy Murray (3): Serena Williams, who practiced with fellow Mouratoglou Academy member Chardy during the offseason, is jokingly taking credit for the Frenchman's success. But it's not clear if even sessions with Serena will be enough for Chardy to overcome Murray.
Murray has won four of their five meetings, with the lone loss coming in Cincinnati last year shortly after Murray won the gold medal at the Olympics.
Murray also is the fresher player -- he hasn't dropped a set so far, while Chardy has gone four or five sets in all his matches. And in his usual fashion, the U.S. Open champ has quickly broken down his opponent's game.
"He serves well, he's very aggressive off his forehand. His backhand is his weaker side, for sure," Murray said. "He hits a lot of slice, doesn't come over it too much. He likes to come forward. He can be erratic, but when his game is on like it's been the last few rounds, he's a very tough player to play because he doesn't give you too much rhythm."
Chardy plans a full-out attack, but it'll take a lot of big serves and forehands for him to make an impact in this match.
Prediction: Murray in three sets