Nick Hundley had two hits for the Padres (3-3), including an RBI double in the second inning. He added a single in the fourth. San Diego shortstop Everth Cabrera had two hits and scored twice.
The Padres scored first, as Jesus Guzman had an RBI single in the first inning.
Jordan Pacheco had two hits and knocked in two runs for the Rockies (3-2), one coming on a double off Weber in the fourth inning.
San Diego pitcher Sean O'Sullivan, making his second start of the spring, allowed one run on two hits with two walks in three innings. He ran into a little bad luck when a potential double-play ground ball hit the foot of an umpire, resulting in an infield single for Rosario.
O'Sullivan, a non-roster invitee, has allowed one run in five innings this spring. Luke Gregerson, one of the best late-inning relievers in the National League, tossed a scoreless seventh inning.
Colorado pitcher Tyler Chatwood -- a candidate for the fifth starter job -- allowed two runs on five hits with one walk and two strikeouts.
"I felt good," Chatwood said. "I felt like I commanded the zone really well. I could have finished off some guys in 0-2 counts a little earlier. Threw a little too many pitches there, but overall I felt good about it."
Drew Pomeranz followed Chatwood and allowed one unearned run over two innings.
The Padres' other squad dropped an 11-6 contest to the A's in Phoenix with Bud Black at the helm. The game in Peoria was managed by Padres bench coach Rick Renteria, who next week will skipper Team Mexico during the World Baseball Classic.
Up next: The Rockies return home to Salt River Fields Thursday for a 1:10 p.m. MT tilt against the Reds. Juan Nicasio starts for the Rockies, and the right-hander needs a good outing after a four-hit, four-run outing in which he faced 10 batters in 1 2/3 innings. Nicasio is on the bubble for a rotation spot and needs to elevate his game if he wants to get traction. Jeff Francis, who threw two scoreless innings in his first appearance, will follow Nicasio.