"Only a few players in the world have perfected the technique that Gareth has," said the American.
"It's when you can strike with an open foot and you sort of come over the ball. A lot of times there's no spin on the ball.
"As a goalkeeper you can't tell where it's going to go, and it moves in the air. It's not impossible to stop, but it's very difficult.
"When games are tight sometimes they're won on such small margins like set pieces - free kicks and things of that nature. Gareth having that in his repertoire is fantastic for us."