Everyone knows that to be a great athlete you need strength, stamina, speed and agility. But what about the mental side of sports?
"Mental toughness is a huge part of tennis," explains Hong Kong International School student Sabrina Woll.
"It can get really mentally demanding since during a match you're out on the court completely alone, with no one to coach or guide you other than yourself. I've had a lot of difficulty with staying confident in a match and believing in my ability to win, as well as staying tough enough in my head to try and win a more challenging match."
But this 16-year-old tennis star says flying solo is also one of her favourite things about the sport. "I just love that I only need to rely on myself," she says. "Tennis is an individual sport and I can only depend on myself in a match."
That's tough, though, because the sport can be very unpredictable. "In tennis, anything can happen on any given day, no matter who the opponent is," she says.
Sabrina is no stranger to the pressures involved in playing an individual sport. She first picked up a tennis racquet when she was just six, and began competing at age 10.
"My whole family is really into tennis," she says, "so I grew up always watching tennis on TV and just playing for fun with my family. I started to get more serious about it when my coach at the time suggested I try playing in a local tournament. I loved the feeling of competing and decided that I wanted to continue doing it."
Sabrina has been playing in International Tennis Federation (ITF) matches across Asia for the past six years. This includes her proudest moment: representing Hong Kong at the Junior Fed Cup tournament in 2014 in Malaysia.
"It was a team of me and two other girls from Hong Kong, and we got to play against all countries in the Asia-Oceania region," she says. "It was a really cool experience and I got to compete with players on a whole new level."
Another benefit: Sabrina's sport takes her all over the world, such as to last month's ITF Junior Tennis Tournament in Colombo, Sri Lanka, where she made the quarter-finals. She says: "I love how playing tennis, specifically playing ITF tournaments, gives me the opportunity to travel and see the world - as well as play my favourite sport."
What song/movie title best describes you when you're playing your sport?
Gotta Have It by Jay Z.
You can have any superpower you choose for 24 hours. What do you choose and how do you use this power?
Teleportation. I would teleport to all the different places in the world I want to go to and see as much of the world as I can in 24 hours.
If you could have an unlimited supply of anything, what would it be and why?
Liveliness. Not only would an unlimited supply of energy help tremendously with my tennis, but it would also just allow me to accomplish so much more in my life in general.