Kansas City starter Yordano Ventura tossed two scoreless innings and teammate Kendrys Morales had a run-scoring double in the third inning as the Royals (0-3) jumped out to a 1-0 lead.
Ventura, likely the No. 2 starter in the Royals' rotation, allowed a double to Matt Kemp in the second inning and little else, striking out one.
"I thought he was great," Royals manager Ned Yost said of Ventura. "I thought Yordano was sharp. Good changeup, good curveball. Everything was sharp."
Trailing, 1-0, the Padres (1-2) tied the game in the seventh inning when Austin Hedges sliced an opposite-field double into the right-field corner, scoring Nick Noonan from first base.
San Diego starting pitcher Colin Rea retired the first five batters he faced before allowing two singles and a walk to load the bases in the second inning. But Rea, contending for a spot at the back end of the team's starting rotation, struck out Drew Butera looking on a curveball to escape the jam.
"I thought he looked good early out of the windup," Padres manager Andy Green said of Rea. "I'm a big fan of the curveball. I talked to [catcher Derek Norris] and that's a big deal for his pitch selection."
All told, Rea struck out two, allowed two hits and a walk in a 41-pitch stint that saw him throw 25 strikes.
Lorenzo Cain, the Royals' starting center fielder, left the game in the fifth inning after being hit by a pitch on the instep of his right foot. One inning earlier, Cain had a double that set up the team's first run, scoring when Morales also doubled.
Cain was replaced in the game by Brett Eibner. His injury was not considered to be serious.
San Diego pitcher Carlos Villanueva allowed one run in two innings and had two strikeouts in his Padres debut. Villanueva appears to be the frontrunner for the team's long-relief role.
Kansas City reliever Matt Strahm tossed two scoreless innings in relief of Ventura, striking out two.
Padres up next: The Padres play their first road game of the spring at 12:10 p.m. PT Saturday when they face the Rockies at Salt River Fields in Scottsdale. The team's Opening Day starter, Tyson Ross, makes his first appearance of the spring. He'll likely go one or two innings. Ross saw plenty of the Rockies last season, posting a 3.80 ERA in four starts. After being off Friday, new shortstop Alexei Ramirez, who had an RBI single on Thursday, will be back in the team's starting lineup.
Royals up next: The Royals return to Surprise Stadium on Saturday for a 2:05 p.m. CT game against the White Sox. Right-hander Ian Kennedy, who signed a five-year, $70 million deal this offseason, makes his first spring start for the Royals.