PHOENIX -- Pavin Smith's three-run homer -- his second this season out of the leadoff spot -- helped the D-backs jump on the Rockies early en route to a 7-5 win in a Memorial Day matinee at Chase Field.

In 39 games this season, the left-hander has batted leadoff, second, third, fifth, sixth, seventh and eighth. Smith’s big swing helped Arizona erase an early 4-0 deficit with a five-run second inning that gave the D-backs a lead they wouldn’t relinquish.

Along with moving up and down the batting order, Smith has played first base and right field, while also serving as a pinch-hitter and the club's designated hitter -- which is what he did on Monday.

“I’m asking a lot of him,” skipper Torey Lovullo said. “He’s leading off against right-handed pitching. That’s more a product of him just being able to see balls and strikes, get good pitches to hit, and find himself getting on base.”

Smith's big home run -- “the difference in the ballgame,” according to Lovullo -- helped turn around some otherwise rocky numbers at the plate amid the lineup-hopping.

“It’s definitely been frustrating. I feel like I’m just missing some balls recently,” Smith said. “To be able to finally put a good swing on one feels pretty good.”

Arizona starter Ryne Nelson was coming off his best outing of the season, only to get hit hard in his five innings of work Monday. After the righty allowed just one run on three hits over six innings against the Phillies last Tuesday, the Rockies tagged Nelson for five runs on eight hits and three walks over five innings.

That set the stage for a long shutdown relief situation for Drey Jameson.

Jameson is only recently back with the big league club after being optioned to Triple-A Reno last month as he struggled with his command. And that came after Jameson lost his bid to crack the starting rotation coming out of Spring Training.

Jameson, however, came within one out of a four-inning save, instead settling for 3 2/3 scoreless innings. He struck out six and walked one while throwing 59 pitches. The right-hander escaped a two-on, two-out jam in the eighth by getting Kris Bryant -- representing the potential go-ahead run -- to line out to second baseman Josh Rojas.

Andrew Chafin came on to strike out pinch-hitter Elehuris Montero on six pitches for the critical final out to pick up his eighth save of the season.

“It just shows you that nothing is guaranteed,” Jameson said of his rollercoaster ride in the season’s first couple of months. “You’ve got to make pitches and you’ve got to get outs and you’ve got to win ballgames to stay up here.”

Lovullo said he’s looking for “more of those types of outings from our guys” in terms of long relief roles, but he stopped short of indicating whether Jameson would again challenge to crack the starting rotation.

“I don’t know that answer. I don’t think we’re going to push him back and forth,” Lovullo said. “We’re going to be very sensitive to his health and well-being.”

The pivotal second inning saw Arizona collect six hits, draw one walk and pull off a successful double steal on the basepaths. The D-backs went 4-for-4 on stolen-base attempts on the afternoon.

Two innings later, Lourdes Gurriel Jr. belted his ninth homer to widen the lead. The big offensive effort was enough to offset a 4-for-5 day by Rockies third baseman Ryan McMahon, who drove in three runs and finished a double shy of the cycle.

The D-backs' win opened a four-game series with the Rockies, with Arizona improving to 2-2 on its 10-game homestand.

It also kept the club within striking distance of the NL West-leading Dodgers. Arizona won’t face rival Los Angeles again until Aug. 8.