In spring we saw them in New York City's Madison Square Garden, capturing Rangers Stanley Cup playoff game.

Now in late summer, a trio of Instagram stars -- Brian DiFeo (@bridif), Anthony Danielle (@takinyerphoto) and Liz Eswein (@newyorkcity), who among them have almost 750,000 followers -- were given special access Thursday to NYC's USTA Billie Jean King National Tennis Center, thanks to Evian Water and the marketing firm MKG.

Using the hashtag #evianday and shared on the Evian Instagram feed (@evianwater), the three showed sights from the U.S. Open that few get to see, with a photographic eye few share. Here are some of our favorite pics from these experts:

@newyorkcity: good morning from the racquet stringing
room at #evianday! very cool to see these guys stringing
racquets for some amazing players like Sharapova.

@takinyerphoto: small crowd in the #media room at the
@usopentennis. @bridif @newyorkcity and I are sharing more
photos over on the @evianwater feed! #evianDay

@bridif: I was just on the practice courts
standing 5 feet away from Maria Sharapova!
More shots @evianwater #evianday #pinchme
#usopen #mariasharapova

@newyorkcity: awesome access down in the
photo dugout - gives you a close up view
of the court! #evianday @evianwater

@bridif: One of the many tunnels beneath
Arthur Ashe Stadium; this one leads to the
main stage... #evianday

@newyorkcity: @takinyerphoto roaming around
the empty stadium #evianday @evianwater

@takinyerphoto: #blue and #green from
the #nosebleeds - #evianday @usopentennis

@takinyerphoto: we got access to the roof
of Arthur Ashe Stadium. not a cloud in the
sky for #evianday with @evianwater

@bridif: That's a wrap! Such a fun day
photographing the US Open for @evianwater,
thanks for the opportunity! Manhattan looks
so tiny from the top of Arthur Ashe Stadium.
#evianday #tinyhorizon #nyc