After evening their series with the top team in the majors, the San Francisco Giants turn to their ace to help win it.

The Giants look to win a sixth straight start made by Madison Bumgarner on Sunday against the visiting Chicago Cubs.

Bumgarner (5-2, 2.45 ERA) has posted a 1.69 ERA while going 4-1 in his last six starts. The best effort of that stretch came Tuesday when the left-hander struck out 11 and yielded a ninth-inning homer in a 5-1 victory at San Diego.

"He's got to be where he wants to be right now, the way he has thrown the ball the last (six) starts," manager Bruce Bochy told MLB's official website.

Bumgarner, who has struck out at least 10 in two of three outings, believes he can be better.

"I feel like there's about 10 different things that's different than the way I want it," he said. "Obviously, it's working well the way it is. I'm about to give it up and stick with what I'm doing now. It seems to be working better anyway.

"I mean, the body feels good and my command's good, so ultimately that's all that matters."

Since the start of the 2013 season, Bumgarner hasn't had much to complain about while going 3-0 with a 1.95 ERA in four starts against Chicago. He allowed a run and two hits while striking out 12 in six innings of a 9-1 home victory over the Cubs on Aug. 27.

Chicago (29-12) owns the best record in baseball but has dropped six of 10 following Saturday's 5-3 defeat and is in danger of losing a second consecutive road series.

Though the Cubs broke out for an 8-1 victory that snapped San Francisco's eight-game winning streak Friday, they've been held to three or fewer runs in the other five of the last six.

They managed one run off struggling Matt Cain on Saturday, coming on Kris Bryant's second home run in as many games.

Bryant, 6 for 17 in four contests, went 0 for 3 with two strikeouts against Bumgarner last season. Ben Zobrist is 5 for 6 with a double and a triple against him.

Kyle Hendricks (2-3, 3.51) looks to improve on a 1-2 road record that includes a 5.19 ERA. The right-hander gave up four runs in 5 1/3 innings of a 4-2 loss at Milwaukee on Tuesday.

"I relied on my fastball a little too much,'' Hendricks said. ''Just got to mix up speeds some more, throw in my curveball and my four-seam fastball.''

He went 1-1 with a 5.56 ERA against the Giants (26-19) last season, with the loss coming at AT&T Park.

Buster Posey, 2 for 6 with a double against Hendricks, hit a two-run homer Saturday. He's 10 for 30 in his last eight games against the Cubs.

Chicago right fielder Jason Heyward will be out three to five days with a side contusion suffered while making a diving catch in Friday's 8-1 victory.

"It's encouraging," manager Joe Maddon said. "When I went out there, I saw him crunched against the wall, laying on the ground. I was not too optimistic. When he stood up, that told us a lot."

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