Maria Sharapova says that even though Serena Williams is aging, she still is at the top of her game.

“You can’t say someone is on the edge of the cliff when they are No. 1 in the world,” Sharapova said in Brisbane, which she will compete in as the top seed. “She still came through and finished the season strong. Even though she’s 33 years old she’s still very strong and very powerful and has so much experience and that shows when she plays on court.”

Williams, who went 22-2 after Wimbledon, including titles at the U.S. Open and WTA Finals, will play in the Hopman Cup this week. Sharapova will receive a bye in Brisbane and could play Sabine Lisicki in her opening match.