John Isner plays his first match since pulling out of his Australian Open opener with an ankle injury, hitting 20 aces in a three-set win over Michael Russell at Delray Beach on Tuesday.

Isner was unable to play in the United States' Davis Cup tie against Great Britain earlier this month because of the injury. The American No. 1 also missed part of the start of last season with a knee injury.

"I played for two hours and no issues [with the ankle],” Isner said. “I'm so happy about that. If I was walking off this court a loser I'd still be happy.''