They were supposed to just hit the ball right back to each other. Keep the rally going. This was a practice drill, after all, not a match.

But when you’re the best tennis players for your age on P.E.I., you train together almost every day and you happen to be sisters, there’s bound to be some sibling rivalry.

When 14-year-old Maggie Chong and her 11-year-old sister Tiffany get on the court together, their competitive instincts are difficult to resist.

“I’m a competitive person,” Tiffany said. “I always try to win the point.”

That, however, can sometimes be a challenge for the