NEW YORK — Perhaps that No. 2 in front of Roger Federer’s name made Maximo Gonzalez believe he had a shot at knocking off the four-time defending U.S. Open champion.

Not so fast, Maximo.

For a while in the first set, Federer couldn’t shake Gonzalez, who was making his Flushing Meadows debut Tuesday night. No easy task any time, but way worse to get your feet wet against the man that had been ranked first in the world for 4 1/2 years until last week.

“One or 2 is always pretty much the same thing,” the 27-year-old Federer said of his seeding. “The change I feel is fans are really supporting me and telling me I’m still No. 1 and still the best.”