Shields retired 10 in a row before the Rangers scored in the fourth.
Beltre and Cruz singled with two outs. Mitch Moreland then lofted a soft single to center that scored Beltre and put the Rangers ahead 1-0.
Tepesch grew up in Blue Springs, Mo., about 15 minutes from Kansas City's Kauffman Stadium. The right-hander needed only eight pitches to retire the side in the first and recorded nine groundball outs through four innings.
Kansas City tied the game in the fifth when Lough singled with one out and scored on A.J. Pierzynski's passed ball.