If the Pittsburgh Pirates are to have any chance of catching the Chicago Cubs, they'll need to start winning games against their division rival - and soon.

With its ace on the mound, Pittsburgh attempts to avoid a second three-game sweep this month at the hands of the NL Central leaders Sunday.

Juggernaut Chicago (27-8) enters the finale nine games ahead of the Pirates thanks to the best 35-game start by any team since Detroit went 30-5 in 1984. Five of those wins have come against Pittsburgh by a 37-11 margin.

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''We're just plugging away right now and understanding that we've got to get up for every ballgame,'' outfielder Jason Heyward said.

Saturday's matchup again wasn't close, with home runs from Anthony Rizzo and Addison Russell backing Jake Arrieta's eight strong innings in an 8-2 rout.

Arrieta yielded three hits and struck out 11 to win his 18th consecutive regular-season decision. Including last year's wild-card game, he's beaten Pittsburgh four times during seven straight Chicago wins in the series, with Cubs hurlers combining for a 1.29 ERA.

''It's just not against us, it's everybody,'' Pirates catcher Francisco Cervelli said of Arrieta. "He's good. He's confident, he knows what he is doing.''

Chicago, which recorded a sweep at PNC Park from May 2-4, continues to pummel Pittsburgh pitching. The Cubs have batted .318 in this year's five matchups and homered three times in Friday's 9-4 win.

Rizzo, who went 2 for 5 with four RBIs on Saturday, is 11 for 23 with two homers and seven RBIs in the season series.

The Cubs reached Gerrit Cole (3-3, 3.78 ERA) for five earned runs in 4 2/3 innings of a 7-2 win May 2, his first encounter with Chicago since allowing four runs on two homers through five innings of the wild-card game. He bounced back by holding St. Louis to two runs in six innings last Sunday in a 10-2 victory, his third in four starts.

Cole has been a nemesis in the past, as his five wins against Chicago since the start of 2014 are the most of any pitcher. He's been particularly troublesome at Wrigley Field, where the right-hander is 5-1 with a 2.68 ERA in six starts and hasn't permitted a home run in 37 innings.

Rizzo is 8 for 20 against Cole and Russell 3 for 9. The young shortstop, who had a three-run homer in the series opener and a two-run shot Saturday, owns a .339 average with 22 RBIs in 16 home games this season.

Pittsburgh (18-17) has lost eight of 11 and draws another tough matchup in Jon Lester (4-1, 1.96), who moved to 3-0 with a 1.17 ERA over his last four starts after allowing three runs in six innings of Tuesday's 8-7 win over San Diego.

The left-hander tossed 5 2/3 scoreless innings in a 6-2 victory over the Pirates in his previous start May 4, giving him a 3-1 record and 1.26 ERA in his past four versus Pittsburgh.

Lester's lone loss over that stretch came opposite Cole at Wrigley on Sept. 25, a 3-2 defeat in which Cole yielded a run on in seven innings. Lester went seven and allowed two runs.

Pittsburgh's Andrew McCutchen is batting .382 in an eight-game hitting streak but is 2 for 16 lifetime against Lester.