The Rangers have won six in a row and nine out of 10. They head back to Texas for a 10-game homestand.
Texas battled back from a two-run deficit, taking the lead in the sixth when Yorvit Torrealba drew a bases-loaded walk.
Only one Texas run scored on a base hit, that coming on a fifth-inning single from Alberto Gonzalez. The other runs came in on a fielder's choice grounder and a sacrifice fly.
Darvish (9-4) gave up five hits, three of those in the second inning when the Padres scored their only runs. He walked three while throwing 122 pitches.
Dale Thayer (0-2), the second of six San Diego pitchers, forced home the go-ahead run to take the loss.
Joe Nathan allowed a hit in the ninth before picking up his 15th save. He has converted 13 consecutive save opportunities.