CINCINNATI -- Austin Jackson hasn't had any problem getting comfortable since being acquired by the Chicago Cubs in August.

"As you can tell, this is a real loose group of guys," Jackson said. "When you're in the role I'm in, you want to do everything you can to contribute."

During the past two games, Jackson has felt at home at the plate as well.

Jackson homered and Jason Hammel pitched five shutout innings, lifting the Chicago Cubs to a 5-3 victory over the Cincinnati Reds in the finale of a three-game series on Thursday afternoon.

The three-run blast gave Jackson eight RBIs since the third inning of Wednesday night's game.

"That’s a nice month for him," Cubs manager Joe Maddon said. "Sometimes it's not the glamour (trades). A lot of times it's how a guy fits in."

It rained steadily through most of Thursday's game but not enough to result in the 19th rain delay this season at Great American Ball Park.

Chicago (94-65) won its fifth straight game to pull within two games of the Pittsburgh Pirates in the battle for home field in the National League wild-card game.

Cincinnati (63-96) has lost 12 straight, its longest streak since 1993.

"The caveat to this terrible season is the guys haven't quit," Reds manager Bryan Price said. "It's been terrible, but I have no complaints about the effort.

"We anticipated competing for a division title. It lasted a third of the season and we had to move some pieces. We know where we're headed, but the win-loss situation is hard to work through."

Jackson, who had a career-high five RBIs in Wednesday night's win, crushed a 1-1 pitch from Reds right-hander John Lamb into the left-field seats for a three-run homer, putting the Cubs ahead 3-0.

It was Jackson's first home run in a Cubs uniform, his last coming Aug. 30 with the Seattle Mariners.

Jackson then made a running catch on second baseman Brandon Phillips' liner to strand two runners in the third.

The Cubs added a run in the fifth on first baseman Anthony Rizzo's ground-rule double into the left-field corner that drove home center fielder Dexter Fowler and put them ahead 4-0.

Rizzo was the last batter for Lamb (1-5), who gave up five earned runs and struck out six in 4 2/3 innings.

"I know when I fall behind (in the count) it doesn't up our chances,” Lamb said. “I have to prepare. I need to do what got me here. I have to find a way to believe in myself."

Hammel (10-7) pitched out of jams in the third and fourth but scattered only five hits through five innings. He struck out five and did not walk a batter before exiting after 86 pitches.

"He had a good fastball, everything was working for him," catcher Kyle Schwarber said.

Maddon said the plan going into Thursday's game was to get some innings out of relievers.

"I was surprised," Hammel said. "Obviously, when you're working out of a funk, you want to keep going."

A play in the sixth inning epitomized the Reds' season.

After Phillips produced his 300th career double and stole third with no outs, right fielder Jay Bruce lofted a shallow pop fly to third baseman Javier Baez.

Phillips strayed too far down the line from third and was retired in a rundown for a 5-2-6 double play.

Cincinnati scored three unearned runs in the seventh.

Center fielder Jason Bourgeois beat out a potential inning-ending double play grounder with the bases loaded to drive in a run. Two-out RBI singles by first baseman Joey Votto off Clayton Richard and Phillips off Trevor Cahill reduced the Cubs' lead to 5-3.

But Hector Rondon pitched a scoreless ninth for his 29th save.

"We're good and we knew that," Hammel said. "It's nice to see it come together so quickly."

NOTES: The Cubs went 19-9 in September, the best record in the major leagues. The 19 victories were their most in September since 2003 -- accomplished for just the second time since 1946. ... Cubs manager Joe Maddon plans to meet with his coaching staff Monday to finalize the roster for Wednesday night's National League wild-card game against the Pittsburgh Pirates. ... Reds 1B Joey Votto (stinger in upper back, neck) and 3B Todd Frazier (slight strain in right Achilles) returned to the lineup after sitting out Wednesday's game. ... Votto singled in the seventh inning to extend his on-base streak to 47 games, longest by a Reds batter since Pete Rose in 1978. ... Reds LHP John Lamb doubled in the third inning for his first professional hit.