Juan Martin del Potro speaks to the media after the 6-3, 3-6, 7-6(2), 6-4 win against Thanasi Kokkinakis
Q. Can you talk about the match. It was obviously a tough one. After he took the second set, how did you get back on track?
JUAN MARTIN DEL POTRO: Yes, it was really tough match. That's what I expected before the match. He has a good game to play on grass, and he serves really, really fast. He moves well from the baseline.
But I think he made an easy mistakes in important moments of the match. I took all the chances to survive. I started to play better. I feel confidence with the results in the end of the match.
Q. How are you physically? You both slipped during the match.
JUAN MARTIN DEL POTRO: No, no, I feel good. Is normally on this surface. But it was nothing dangerous. To be in my first match on grass after long time, I think I moved well.
Q. You had a bit of a groin injury. How did your body feel after a tough match?
JUAN MARTIN DEL POTRO: I think everything is fine. Nothing worst, which means something good to me. Is a good signal for prepare my next round.
I will see how is my practice tomorrow. But I think my body is in good shape at the moment.
Q. How slippery is the grass? What is the mental and physical approach to dealing with that?
JUAN MARTIN DEL POTRO: Well, always is slippery. But you must to deal with that. You have to learn the movements on this surface. At the beginning of this tournament, is complicated to move. But in the end, when the court is dried and the sun comes out, is much easier to move.
Q. What about what you wear on your feet, is it different? How do you make the selection?
JUAN MARTIN DEL POTRO: It's not easy to make the selection of the movements. You have to play 100% all the time. But normally when you feel the both foots on the grass, you can hit hard the ball, you must win the point.
Q. How do you choose what shoes to wear?
JUAN MARTIN DEL POTRO: We have only kind of shoes to play on grass.
Q. When you lost the second set, 3-1 in the third set, were you worried you must be heading out?
JUAN MARTIN DEL POTRO: No, no. I think I had lucky because I broke back very, very soon. I was keeping my serve. What I say, he made mistakes in the tiebreak, and I won than a easy tiebreak for a tough match.
Then in the fourth set, I broke almost in the end. Then I close the game with my serve, playing good games, good points.
Q. How pleased were you with the overall level of your performance today?
JUAN MARTIN DEL POTRO: I think I played a good match, to be my first match on grass after long time. I'm looking forward to playing better in second round.
Q. What was your state of mind when he saved a few match points?
JUAN MARTIN DEL POTRO: No, nothing, because he returns very well to my foot, onto the lines. I was serving really good my first serve. I made few aces in that game. I didn't make a double-faults.
He plays good points. I had lucky because after many matchpoints, I could close the match with a good forehand.
Q. Four years tomorrow since your epic semifinal with Novak. What can you recall?
JUAN MARTIN DEL POTRO: It was a great battle for both. I have great memories from this tournament. Hopefully I can be in the last day of the tournament one day again.
Q. I'm sure you know who you face if you make it to the third round.
JUAN MARTIN DEL POTRO: I know. But I have to win my second round first.
Q. Thanasi is a player, like you, who has had long battles with injuries over the years. Can you identify with that or sympathize with that? Do you have any relationship with him, might have talked to him about what you went through, have any advice for him?
JUAN MARTIN DEL POTRO: Well, I don't know him really much. But he's pretty young. He has to deal with all these pains. I mean, the tennis, he has everything to play good tennis in the future. But the body and the health are first of all.
My advice, trying to stay strong mentally all the times, listening to the doctors, listening to the physios, then the tennis come after all these things.
Q. You play Ernests Gulbis next. He's someone who went into the top 10, then kind of disappeared. What are your thoughts on him, his game? He's peculiar as a person.
JUAN MARTIN DEL POTRO: Everybody knows how good is Ernests on this surface. He has a good day, he can beat all the guys on tour. I have to be focused doing my job, doing my serves and forehands. If he give me a little chance to break the serve, trying to take it.
Q. You've been here a lot over the years. How do you feel now in terms of your form and health compared to the other years?
JUAN MARTIN DEL POTRO: I feel older (smiling). But I feel good. I decide to came and play here because my body's okay. I'm not putting in risk anything of my body. I have one day off to recovery. I'm feeling strong enough to play my second round.
Q. Your form?
JUAN MARTIN DEL POTRO: I think I'm playing good tennis. This year I had some loses against the top guys. I'm almost 30 in the world, which means good to me after all my injuries. Of course, I can be better in the future, but I'm working hard for do it.
Q. What goes through your mind when you are in the situation of slipping and how do you avoid getting hurt?
JUAN MARTIN DEL POTRO: We cannot manage the slippery of the court. We never knows when we going to slippery. But you have to sometimes take the moments to go hard to the ball or not. I mean, if you are Love-40, and the game just started, maybe you have to put and risk your body running for a ball. You know what I mean?
Q. Depending on the situation.
JUAN MARTIN DEL POTRO: Depends, yeah.
Q. On the play today, what was going through your mind?
JUAN MARTIN DEL POTRO: I couldn't take any moment. I run hard to every ball.
Q. When you slipped, what were you thinking as it happened?
JUAN MARTIN DEL POTRO: That's happens every time to me.