The phrase "first goalkeeper" refers to the primary or main goalkeeper in a team or game. They are usually the first choice for defending the goal and stopping the opposing team from scoring. Full definition
In 1996, Carlos Bossio becamethe first goalkeeper in Argentine football to score with a header, after heading home the equaliser from a corner for Estudiantes in a game against Racing Club. (goalkeepersaredifferent.com)
.@PetrCech becomes the first goalkeeper reach 2?? (caughtoffside.com)
He is young strong loves arsenal and wouldn't be the first goalkeeper to lead arsenal (justarsenal.com)