Standard deadpan catchphrase by ESPN SportsCenter anchor Dan Patrick, typically uttered when an athlete repeatedly succeeds at a particular task, most frequently when an NBA player drills 3-pointer after 3-pointer.
It was a reaction to the sportscaster cliche, "He's on fire!!!" being shouted into the mike by every Tom, Dick, and Harriet calling a game. Patrick instead very quietly says, "Kevin Garnett was...en fuego."
Originally, he said "el fuego." Then a high school Spanish teacher from Pennsylvania wrote in and gently pointed out that he was announcing that Kevin Garnett was the fire rather than on fire. Thus chastened by our public education system, Dan Patrick made "en fuego" a cliche in its own right.