Hill -- who signed a contract that will earn him $40.5 million over the next four seasons -- homered, doubled and singled while driving in four runs.
Cahill -- on a diet that has him 10-15 pounds lighter than a year ago -- gave up one hit in five scoreless innings. The No. 2 starter in Arizona's rotation struck out five and walked two.
"The best he's thrown it this spring," manager Kirk Gibson said. "I thought the last inning was his best inning. He threw two really nice curveballs that inning and some changeups. He threw many more strikes today, had better command of where he wanted to throw it as well."
Cahill said he lost the weight for "overall health" reasons.
"I've always done the same work and running and stuff," he said. "It was just the diet. I would eat unhealthy. Maybe (now) I'm not sick one time a year. If I'm sick, usually once a year, then that start's a struggle. If I'm healthy maybe it might contribute another win or whatever."
Hill's big day, in front of a record crowd of 12,809 at Salt River Fields, boosted his spring batting average to .452 with nine RBIs in 11 games.
Despite the big contract, Hill said, "you never want to get comfortable" in this game.
"It is comfortable, yes, family speaking," he said. "Everyone's happy. We love it here. So it's nice knowing you're going to be in a spot for a couple of years, but every year you've got something to prove. You want to go out and you want to be better than the last year."
Ted Lilly had a rough start for Los Angeles, allowing five runs and five hits in two-plus innings. He faced five batters without getting an out in Arizona's four-run third.
Dodgers slugger Matt Kemp hit his first home run of the spring.
Rod Barajas, competing for Arizona's backup catcher job, hit a two-run homer. Hill doubled in a run in the first, singled in a pair with the bases loaded in the third, then led off the fifth with his first home run of the spring.
Adam Eaton singled twice, walked and scored two runs for Arizona.
"Too many hits," he said. "I lost command, fell out of my rhythm."
Eaton led off the fourth with a walk and went to third on Martin Prado's single. Jason Kubel walked to load the bases for Hill, who singled sharply to left to bring in two runners. Miguel Montero followed with an RBI single and Lilly's day was over. Eric Chavez brought home the fourth run of the inning with a sacrifice fly.
Lilly's return from shoulder surgery has been slowed a bit by a nagging cold and the fact that one outing was halted after two-thirds of an inning due to a storm.
This was his third appearance, and first start, of the spring, not counting the rain-shortened outing. The left-hander pitched 2 2/3 innings of relief Tuesday against Cincinnati, giving up five runs but only one earned.
"My arm's fine," he said. "I want to get better. I'd sure like to get back out there. The outing was supposed to be better than that."
Yasiel Puig, the 22-year-old Cuban signed by the Dodgers a year ago to a seven-year, $42 million contract, singled in the first and stole second and third. He went 1 for 2 to give him a .452 average this spring. Puig had a two-run homer and two singles in three at-bats against Kansas City on Saturday.
Both teams wore green caps for St. Patrick's Day. ... Eaton has hit safely in nine of 11 games. ... Lilly used a neon green bat, but there was no luck of the Irish in it. He struck out in his only plate appearance. ... Dodgers RHP Zack Greinke threw off a mound for the first time since he was shut down last Monday with inflammation in his right elbow. Greinke threw 38 pitches and said he felt good in his first session since his right elbow was injected in Los Angeles with plasma rich in platelets.