Spanish second seed Rafael Nadal responded to the challenge thrown to him by 2014 champion Marin Cilic as he battled to reach the US Open quarter finals with a four set win.
Nadal, had too much quality for the Croatian Cilic in a 6-3, 3-6, 6-1, 6-2 victory in New York.
Cilic, briefly rediscovered his best form to level before wilting.
Nadal, the 18 time Grand Slam champion, will now play Argentine Diego Schwartzman in the last eight.
Argentine Diego Schwartzman came from a set down to beat German sixth seed Alexander Zverev and reach the US Open quarter finals.
Schwartzman, won 3-6, 6-2, 6-4, 6-3 and will next face Rafael Nadal who overcame Marin Cilic in four sets .
A frustrated Zverev was docked a point for an obscenity in the final set after earlier hitting a ball into the crowd.
French man Gael Monfils cruised past unseeded Spaniard Pablo Andujar 6-1, 6-2, 6-2 to make the last eight.
Monfils, broke serve six times and did not face a break point as he won in one hour and 26 minutes to set up a meeting with Matteo Berrettini.
While Italian Berrettini, saw off Russian Andrey Rublev 6-1, 6-4, 7-6, 8-6 to reach a Grand Slam quarter final for the first time.
Berrettini, had failed to progress beyond the first round in two previous attempts in New York.