"He's really driving the ball and he's not missing pitches," manager Joe Girardi said of Rodriguez. "It took him a little time to get his timing back, but he looks really good."
The Yankees (39-33) improved to a season-high six games over .500 and have won nine of their past 11 games. During the winning streak, New York has outscored its opponents, 43-11.
The Yankees are 19-9 since Rodriguez's return from the disabled list May 20, averaging 5.86 runs per game during that stretch. Still, the third baseman doesn't look to be stopping soon.
"We still got a long ways to go," said Rodriguez, who was 3-for-4 with two RBIs, two runs scored and a stolen base against San Diego (31-42). "I mean, all facets of our game have to continue to improve and get better. We're playing well, but we have a long ways to go."
The Yankees were 6-11 and averaged 3.5 runs per game during the 17 games Rodriguez missed with a strained right quadriceps.
"Any time you insert the best player in the league, it's going to get better," said Johnny Damon, who was 3-for-5 with two RBIs, one run scored and a stolen base. "It's kind of good he's been flying under the radar.
"People are talking about Jason [Giambi's mustache] and my hitting streak, and he's kind of just going about his business and driving in tons of runs."
The Yankees jumped on Peavy, the National League's reigning Cy Young Award winner, for four runs -- three earned -- in four innings. Peavy (5-4) yielded six hits, walking two and striking out four.
A first-inning fielder's choice and error gave the Yankees an early advantage before Wilson Betemit and Damon stroked run-scoring hits in the second inning.
Coming off his worst start of the season, Rasner (4-4) wasn't perfect, but the results improved. The right-hander limited San Diego to two runs on three hits over five innings, striking out four -- all in the first two innings -- and walking a season-high five, after not issuing more than two free passes in any professional start this year.
After cruising through the first two innings, Rasner struggled in a lengthy third, though he limited the damage to two runs by pinning the bases loaded. The Padres closed ground on Edgar Gonzalez's two-run double to left-center, scoring Khalil Greene and Jody Gerut, but that was all Rasner allowed, posting his first victory since May 21 vs. Baltimore.
"I struggled with my command, but most of the hitters bailed me out tonight," Rasner said. "They did a great job. We had some great plays behind me. It's always nice to get back in the win column. It seemed like it's been a long time. It feels good, absolutely."
Added Girardi: "It wasn't as smooth as most of his starts have been, but he did a nice job giving up just the two runs in five innings and he gave us a shot to win."
A healthy Rodriguez certainly helps the team's chances, too. After a one-hour, 18-minute rain delay, the Yankees began another game with an important player who thinks his physical problems are behind him.
"I think so, I hope so," Rodriguez said. "You [have] to really not take anything for granted and make sure you do all your rehab and stretch really well. Days like today are more challenging just because of constant delays."