PHOENIX -- Rookie Junior Lake is making quite a splash in his first week in the major leagues.
Promoted from Triple-A Iowa after the All-Star break, Lake hit his first major league home run, had his first career four-hit game and drove in three runs Monday in the Chicago Cubs' 4-2 victory over the Arizona Diamondbacks.
Lake's two-run homer on a 2-0 pitch in the fifth inning staked emergency starter Chris Rusin (1-0) to a 3-0 lead.
"It felt good," Lake said. "I was pretty excited. Everybody was crying when I hit the home run. I was just looking for a fastball."
Lake also singled home an insurance run in the ninth inning. His other two hits were bunt singles, one down the first base line and one down the third base line.
He has nine hits in his first four games, the first Cub to do that since Andy Pafko in 1943.
"One of our better athletes in the minor leagues, and to come up and do something that has never been done in 70 years is pretty impressive," Cubs manager Dale Sveum said. "You see what kind of power he has, and the last hit was his biggest hit since he has been here. To add on like that against a guy he has never seen (Will Harris), to hit a breaking ball, that was huge."
Rusin (1-0) gave up only two hits and two walks in five-plus innings after being recalled from Triple-A Iowa to replace No. 1 starter Matt Garza, who was dealt to the Texas Rangers earlier in the day. In the trade, the Cubs received right-hander Justin Grimm, minor league third baseman Mike Olt, minor league right-hander C.J. Edwards and two players to be named.
"You just have to step up when they call you and be ready anytime," Rusin said. "I was ready for the opportunity, and I was able to throw strikes and help our team win."
Kevin Gregg pitched a scoreless ninth for his 19th save for the Cubs (44-53), who had lost three of their previous four.
Shortstop Didi Gregorius had three of the D-backs' six hits, including a bloop double down the right field line that led to a two-run sixth inning, cutting the Cubs' lead to 3-2.
"You can't be perfect in this game. We keep battling no matter what. We have to find a way to score," Gregorius said.
The D-backs (51-48) have scored eight runs in their past five games, losing four of them to fall out of first place for the first time since May 18. The Los Angeles Dodgers (51-47) won in Toronto earlier Monday, and they grabbed the top spot in the National League West.
"Things aren't coming very easy for us. We had six hits tonight, and two of them were bloops. The guys are hustling," D-backs manager Kirk Gibson said.
D-backs first baseman Paul Goldschmidt singled in a run for his 78th RBI of the season, one behind NL leader Brandon Phillips.
The Cubs' Dioner Navarro hit a bases-empty homer in the second inning, his ninth of the season, tying a career high set with Tampa Bay in 2007. He was hit by a pitch in the left knee by Tyler Skaggs (2-2) in the fourth.
Skaggs, back in the rotation after a short stint at Class A Visalia to get work during the All-Star break, allowed three runs in six innings. He struck out six and didn't issue a walk.
Rusin struck out four and walked two in his second start of the season.
"I was able to throw my off-speed for strikes, which got me back into counts and be able to get weak contact and got me through the five innings," Rusin said.
NOTES: RHP Brad Ziegler had Arizona's only save opportunity in the first four games after the break, and he will remain in that role, Gibson said. "Kind of make my decision as it goes on within the game, although I did tell 'Ziggy' the other day I was thinking he would be that guy. That's kind of where I am right now," Gibson said of the closer's role. The Diamondbacks have 19 blown saves, tied with the Cubs for the most in the majors. ... Cubs RF Cole Gillespie made a spectacular sliding catch of Aaron Hill's foul fly near the right field stands in the second inning. Gillespie's knees buckled as he slid into the padded wall while making the grab. ... The Diamondbacks could not help but look back at their loss to Milwaukee in the 2011 NL Division Series after Brewers OF Ryan Braun was suspended for the rest of the season Monday. "It's frustrating to know that maybe you were cheated on the other side of it a little bit," Diamondbacks INF/OF Willie Bloomquist said. Braun was 9-for-18 with four doubles, a home run and four RBIs in the NLDS, which the Brewers won in five games. He was suspended for 50 games after reportedly testing positive for elevated levels of testosterone following that postseason, but the suspension was overturned after his appeal. ... Arizona optioned LHP Eury De La Rosa to Triple-A Reno after recalling Skaggs for the start. De La Rosa retired all seven batters he faced in two appearances.