Q. It isn't often that you are out-aced in a match. Is it a question of her being left-handed?
SERENA WILLIAMS: I think when someone is a lefty, they just open the court more. You're expecting one serve. You kind of almost give up one side. You just say, You can ace me on this side, but I'm going to expect that side. So, yeah.
Q. You practiced with her. Is this something you regret when you play them in a major tournament?
SERENA WILLIAMS: No. I love practicing with her. We always practice together in tournaments. Whenever I can, I love hitting with her. I think it helps her game and she helps my game. So it is what it is.
Q. Why so?
SERENA WILLIAMS: Well, as you can see, she gives 100% on the court. She always tries to do the best. She's great. She is an incredible fighter.
Q. There's a kind of open discussion with the men about the five sets in the Grand Slam. I would like to know your opinion about that. Do you feel as a woman a discrimination? Would you like to try a five-set match maybe?
SERENA WILLIAMS: Well, I've said it before and I'll say it again: We don't mind playing five sets. We've offered to play five sets. The tournaments don't want us to play five sets. We're ready, willing, and able to play five sets.
Q. Why do you think they don't want it?
SERENA WILLIAMS: You would have to ask them that. I can't answer that question.
Q. You've been associated with Venus for so long. We almost take it for granted. Take a moment and say what's the best part of hanging out with Venus. When did she mean the most to you?
SERENA WILLIAMS: Wow. I think every day is a great part hanging out with her. Every day, you know, you learn something new about someone. I think that's what life is about, it's about learning something new every day. A partner for me that will be lifetime. She's just a great individual and incredibly powerful woman.
Q. What is something you have learned about Venus recently?
SERENA WILLIAMS: Just about her strength more than anything. Her positivity is second to none.
Q. How important was it to get to the second round? You used to take it for granted. But this year...
SERENA WILLIAMS: To get to?
Q. To the second week, sorry.
SERENA WILLIAMS: I mean, I can't believe I'm in the second week. It's like a dream come true for me at this point (smiling).
Q. Why can't you believe it?
SERENA WILLIAMS: I'm being sarcastic (smiling).
Q. When you play with Venus after the tough loss she had yesterday, do you have to do anything extra to motivate her to be in the match, sister to sister?
SERENA WILLIAMS: No. She was actually incredibly motivated herself. She wanted to do well. She played really well. Her motivation was great. It was really good to see.
Q. Out of curiosity, how many sets have you ever played in a day?
SERENA WILLIAMS: I don't know. Maximum probably would be six, right?
Q. Practice, anything.
SERENA WILLIAMS: I don't play sets in practice ever, ever. Only match play.
Q. With the crazy schedule you've had in singles and doubles, is it even more important that the crowd get behind you?
SERENA WILLIAMS: Well, we love the crowd here. I mean, they're so supportive. Especially in doubles, they're just crazy. It's so awesome to feel and to see. It's such a wonderful feeling. Every year it makes me want to come back and do better.
Q. Was this one of those games where you had to fight to find your rhythm?
SERENA WILLIAMS: Yeah, I definitely had to fight to find my rhythm. At the same time she was playing really well. She was going for shots, getting so many balls back. It wasn't like my shots, she just got them back and hit a better shot at times. For me, it was just about hanging in there.
Q. In the tournament we've seen on the women's side one upset after another. Less on the men's side. Why do you think there have been so many on the women's side?
SERENA WILLIAMS: I don't know. I've been a casualty this whole year at Grand Slams. I'm just hoping to keep staying in there.
Q. Feels good to still be here?
SERENA WILLIAMS: So far. Key word.
Q. What do you and Venus do together to have fun while you're here?
SERENA WILLIAMS: While we're here, we're just focused on the tournament. We're practicing. We're not necessarily having fun. This is our job. We train really hard for it.
Q. Is there anything to read into you asking the ball boy to carry your bag?
SERENA WILLIAMS: No, nothing to read into it. My bag is heavy. I have so many things in there that probably shouldn't be in there. I usually don't carry it, so... It's just so heavy. Plus I think he wanted to carry it (smiling).
Q. You talked about being all business here with Venus. What is the most fun things that you do with her when you're far away from tennis?
SERENA WILLIAMS: I don't know. We just do a lot of fun things. I think when you're away from tennis, you just have to, like -- we just like to sit around at the house because we're gone so much. When you travel so much, it's the best and most relaxing thing to just sit on the couch and not move.
Q. The DJ Nash that has been playing Katy Perry's Roar after your wins, is that to go with your outfit?
SERENA WILLIAMS: Incidentally, I love that song Roar. I listen to it all the time. I love Katy Perry. I think it's an inspiring song. I love the words to it. I think it's great.
Q. You hit more aces than anyone this year. Are there any shots that feel more pleasurable?
SERENA WILLIAMS: No. I love hitting aces. It's not easy, but it makes your life a lot easier. So I like it.
Q. You're into the fourth round, haven't dropped a set. What is the mentality or the mindset?
SERENA WILLIAMS: The same as the first round. You know, just treat every round as if it's your last. Do the best that I can. Just stay positive, you know, 'cause I want to continue to do the best I can.
Q. Have you been able to do that so far?
SERENA WILLIAMS: Yeah, I've been positive. I got a little down on myself today. But lesson learned. Next round I'm just going to go in there and fight as hard as I can and leave everything on the court.
Q. Serena, do you have friends in New York?
SERENA WILLIAMS: Yes, absolutely. As long as it's not during the US Open. During the US Open, I kind of stay in my room and do nothing.
Q. You don't hang out?
SERENA WILLIAMS: No, it's difficult. Especially me, I'm usually playing singles and doubles here so I don't really have time.
Q. Does the leopard print mean the cat suit might be making a comeback?
SERENA WILLIAMS: That's a good question. We all loved the cat suit. At least I did.
Q. Gives us hope.
SERENA WILLIAMS: Keep hope alive.
Q. Where is the cat suit?
SERENA WILLIAMS: Yeah, I have all my outfits. I saw it the other day actually in my closet.
Q. How cool was it to walk out that night? Seemed like everyone was gasping, saying, What the heck?
SERENA WILLIAMS: Gosh, that was over a decade ago, right? I don't know. I was actually nervous because it hadn't been done before.
Q. Sounds like a hashtag campaign.
SERENA WILLIAMS: Right. Of course hashtags didn't exist back then.