After getting the Padres on the board with a solo homer in the fifth, Kyle Blanks put the Padres ahead 3-2 in the seventh with a sacrifice fly, one of three runs for the Padres in the inning.
The Rangers made it 4-3 in the eighth on a two-out, RBI single by Aaron Cunningham.
The Rangers opened the scoring when David Murphy's two-out single plated Ian Kinsler and Beltre. Batting leadoff to get extra at-bats in, Beltre (right calf injury) went 1-for-3, reaching second base in the third on an error. He showed no ill effects of the injury while running the bases or playing in the field.
The Padres were held hitless through three innings by Rangers ace Yu Darvish, who threw 23 of his 39 pitches for strikes.
"Although I didn't have all my pitches today, my slider was working particularly well," Darvish said. "I tried to focus on that pitch as much as possible, and it worked out."
The Padres broke through with two hits in the fourth off reliever Neal Cotts -- one of them a double by Jesus Guzman -- but couldn't get a run across in the frame.
An inning later, Blanks crushed a 3-1 Cotts offering into the Bermuda grass in left-center field, cutting San Diego's deficit to 2-1.
A.J. Pierzynski doubled for the Rangers in the fourth, as he continued his solid spring.
After Guzman led off the Padres seventh by being hit by a pitch, Rico Noel pinch-ran and stole second before Gregorio Petit drove him home with a single. Petit advanced to third on an error before Blanks' fly to center made it 3-2.
Jonathan Galvez delivered an insurance run with a double, scoring Yasmani Grandal, who reached on a pinch-hit single.
Padres left-hander Eric Stults, one of several candidates for a rotation spot, got off to a rocky start but managed to settle down and pitch three solid innings, surrendering two runs on two hits.
Up next for the Rangers: On Tuesday the Rangers have their first day off since games began this spring, and manager Ron Washington doesn't expect any of his players at the team's complex in Surprise. The one Ranger in action will be Derek Holland, who will likely pitch for Team USA in Glendale. The Rangers play host to the Cubs at 2:05 p.m. CT on Wednesday, and left-hander Robbie Ross is looking to continue his strong push for the No. 5 starter role when he gets the ball for the third time this spring in his first start. Beltre will see his second game action of the spring, as well.