(AP) -- While they've been struggling, the Arizona Diamondbacks have to feel good about a visit to Kauffman Stadium.
The Diamondbacks will go for their sixth straight victory in Kansas City on Friday night when they open a three-game series against a Royals team that has struggled to pick up wins at home.
It's been more than two weeks since Arizona last won back-to-back games, and the Diamondbacks (17-22) will try to change that following a 9-7 victory over Colorado on Thursday.
Justin Upton hit a two-run homer in the ninth inning, helping the Diamondbacks post their fourth victory in 15 games. He came into Thursday batting .173 over the previous 13 contests but walked three times before his homer.
"That was nice," Upton said. "Just being able to put all my struggles aside and come up big for the team. That's always a goal, but it's not always that easy. When you can get it done, it definitely feels good."
Arizona swept a three-game series in Kansas City last year to improve to 9-3 at Kauffman Stadium. Upton is 9 for 21 with five doubles in his last five games there.
With Joe Saunders (2-3, 3.43 ERA) taking the mound in the opener, the Diamondbacks appear to have a good chance of continuing their success at Kauffman Stadium.
The left-hander improved to 4-0 with a 2.57 ERA against the Royals after allowing two runs in seven innings of a 7-2 win June 21.
However, after a strong beginning to the season, Saunders has struggled in back-to-back outings.
He gave up six earned runs for a second straight start Sunday, allowing a season-high 10 hits over five innings of a 7-3 loss to San Francisco.
The Royals (15-22) are looking to get back on track after losing a pair to Baltimore this week. They had won six of seven before hosting the Orioles, who won 5-3 on Thursday.
Kansas City, which fell to 4-15 at home, had a lead in both losses. The Royals gave up two runs in the ninth of a 4-3 defeat in 15 innings Wednesday before failing to protect a 3-2 lead Thursday, allowing three runs in the seventh.
"It's real tough because you want to defend home so bad," center fielder Jarrod Dyson told the Royals' official website. "It's kind of frustrating when you know you had the game won."
Kansas City will hand the ball to Luis Mendoza (2-2, 4.76), who is taking Danny Duffy's spot in the rotation after Duffy was placed on the disabled list with a torn ulnar ligament in his left elbow.
Mendoza, who has never faced the Diamondbacks, pitched 5 2-3 innings in relief of Duffy against the Chicago White Sox on Sunday. He gave up one run and seven hits while striking out four to earn the win.
The right-hander made four starts in April, going 1-2 with a 6.00 ERA.
Royals manager Ned Yost said slumping first baseman Eric Hosmer will likely be held out of the starting lineup for a second straight game Friday. Hosmer is batting .174 this season, going 5 for 40 against left-handers.