Fritz enjoyed a positive start in front of a packed house on Arthur Ashe, breaking Tiafoe at the first opportunity to race into a 3-0 lead.
But Tiafoe, one of the sport’s most engaging players, readjusted, winning six of the following seven games to wrap up the first set.
Fritz was much more competitive in the second set, dropping just one point on serve before breaking Tiafoe as he attempted to force a tie-break.
However, any momentum was soon ripped away from Fritz.
Tiafoe broke in the opening game of the third and his powerful serve, combined with some impressive athleticism, saw him take a two-sets-to-one lead.
However, the pressure told. Serving at 4-5, Tiafoe double faulted twice to slip from 40-15 to deuce, before two wild errors gifted the set to Fritz.
Tiafoe struggled to regain his intensity, with Fritz charging into a 4-0 lead before his opponent, willed on by the crowd, regained a break.
However, it was not enough, with Tiafoe immediately going 0-40 down on serve to be broken straight back, and Fritz confidently served out the win.