The D-backs left for their five-game trip to the Bay Area full of confidence and perhaps even a little swagger, riding a six-game winning streak.

They return to Arizona on Sunday night without a win to show for the travel.

The Giants finished off a three-game sweep of the D-backs on Sunday afternoon by a 6-1 margin that dropped Arizona to 13-16 and into last place in the National League West.

• Box score

“This was an extremely frustrating road trip for us,” D-backs manager Torey Lovullo said.

The D-backs open an eight-game homestand Monday with the Rockies. After the four-game set with the Rockies, the Giants come to Chase Field.

Here are three things the D-backs need to do to get back on track:

1. Get offensive

The D-backs' offense struggled at the beginning of the season, but it looked like they had things turned around for about a two-week stretch before things went quiet again in the Bay Area.

“It’s hard to put my finger on it,” Lovullo said. “I got five of them, I’m going to try to figure that out. That’s my job. Offensively, our guys have done it before. They’re motivated. They work their butts off. That’s what’s so hard for me to watch is that I know exactly what their intent is, I know exactly where their heart is. We’re going to keep fighting. I can assure you that. This group of players are easy to believe in.”

In Saturday night’s game the hitters seemed to be overly aggressive as 20 of their 27 outs came on three pitches or less.

Sunday, it wasn’t so much about working counts, but rather Giants starter Trevor Cahill did a nice job pitching to them.

Still, they need to find a way to score multiple runs in an inning. In their last 51 innings, they’ve scored more than one run just once and that was a two-run rally in the fourth inning Friday.

2. Get the bullpen right

It’s been a struggle for Lovullo to find the right combination to get the game from the starting pitcher to closer Archie Bradley.

Kevin Ginkel, Andrew Chafin, Hector Rondón and Junior Guerra have all had their issues and Lovullo has had to juggle those setup roles.

Relievers are going to give up hits, but what is concerning to the coaching staff is the walks. In 14 1/3 innings on this trip, the bullpen allowed 13 walks, and with all that traffic on the bases, it’s no surprise they allowed 12 earned runs.

“For a little while it was carrying us early in the season,” Lovullo said of the bullpen. “Once again, I think we have to get back to certain basics and attack the strike zone with our best stuff. It seems like on a given day, one guy might be grinding through it and give up a couple of runs that might make the difference in the game.”

In fairness to the bullpen, the lack of offense doesn’t really give them much wiggle room.

“If we’re out there scoring runs and posting big numbers, we’re having a different conversation,” Lovullo said. “The margins are so fine, so minute for that bullpen, they feel like they have to walk into the game without making one tiny mistake.”

3. Take advantage of being home

Maybe getting back in familiar surroundings will help, and the Rockies are struggling worse than Arizona right now, having lost seven straight.

The last time the D-backs saw the Rockies, they took two of three at Coors Field and matched a club record for runs in a three-game series there, scoring 32.

“I think we’re going to take it one game at a time,” Arizona outfielder Kole Calhoun said. “What we did in Colorado is in the past. We have to go out and remember who we are as an offense. This is an offense that can go out there and score a lot of runs. We can compete with anybody. I think we ran into some guys that threw the ball well against us and we probably made it a little easier on them by expanding our zones. Hopefully we get back home, get back to our winning ways and get a little confidence going and that swagger back and play ball like we can.”