Kennedy (4-8), obtained Wednesday in a trade-deadline deal with the Arizona Diamondbacks, limited the Yankees to two runs on four hits over 5 2/3 innings. The right-hander overcame four walks and struck out six.
He exited in the sixth with a 6-2 a lead and New York chipped away with a run in the seventh before Colt Hynes fired a scoreless eighth and Huston Street wrapped up the triumph with his 21st save.
Yankees starter Phil Hughes (4-10) was roughed up for five runs on six hits, lasting just 2 2/3 innings.
Notable deaths of 2014 [PHOTOS]
Michael Sam cut from the Dallas Cowboys