Gareth was named Barclays Player of the Month for January on Friday after a fine month highlighted by a superb strike at City and a double in Tuesday night's 3-1 win against Wigan.
In the same month, he was the only Premier League player to be named in the UEFA.com users' Team of the Year for 2011, the first time a Spurs and a Welsh player has made it into that line-up.
"Gareth's brilliant, a top, top player, one of the best around at the moment," said Ledley, who returned to action on Tuesday night.
"He's unstoppable when he's in full flow."
Ledley explained that Gareth's supreme fitness levels allow him to take pressure off the rest of the team, especially late in the game.
"He can do it when a lot of players are tired," added the skipper.
"You know he's going to get the ball, knock it and run past players.
"As defenders we can sit back late on, he picks the ball up in our half and just takes off. It's great for the other players in the team."