IN-GAME::((GIANTS vs CUBS)) ::

The San Francisco Giants are set to face their second straight overmatched opponent.

Based on the difficulty they had sweeping baseball's worst team, the NL West-leading Giants are unlikely to overlook Chicago in Friday's opener - especially after the resilience the Cubs displayed in their last game.

San Francisco (74-57) arrives in Chicago with a season-high 4 1/2-game lead over Los Angeles in the division after beating Houston 8-4 on Thursday. Nothing came easy against the Astros for the Giants, who rallied in the ninth in the opener, nearly coughed up a four-run lead in the middle game and overcame a 4-0 deficit in the finale.

"We kept the energy up just enough to get three wins," said Brandon Belt, who went 4 for 5 with two doubles and an RBI on Thursday, "and hopefully we can keep it going."

The Giants also had trouble putting away the Cubs, owner of the majors' second-worst record, in early June at AT&T Park, though they managed to win all four games. San Francisco outscored Chicago 11-6, winning three times by one run.

Madison Bumgarner (14-8, 2.93 ERA) set the tone for that series, allowing two runs while striking out 11 in eight innings of a 4-3 win on June 1. He is 3-1 with a 1.55 ERA and 37 strikeouts in 29 innings in his last four starts against the Cubs (50-80).

Bumgarner takes the ball after allowing four runs, seven hits and a season-high tying four walks in 6 1-3 innings of Saturday's 7-3 loss to Atlanta. The left-hander had a 1.93 ERA in his previous eight starts.

"It happens throughout the course of a season that you get out of whack," Bumgarner said. "That was the first time all season I wasn't able to get it back."

Although he hasn't had much trouble against Chicago, he'll have to be careful facing Starlin Castro, who is 7 for 16 against Bumgarner - his best average against any pitcher he's faced that many times.

The Cubs have lost 22 of 29, but enter this series in good spirits after rallying to beat Milwaukee 12-11 on Thursday to salvage the finale of a four-game series. Chicago trailed by six and capped a three-run ninth inning with Alfonso Soriano's one-out RBI single.

The Cubs, who had averaged 2.9 runs in their previous eight games, finished with eight extra-base hits and a season-high 11 walks, and hope this outburst is a sign of things to come.

"I think it will help the offense and the clubhouse because we came back," Soriano told the Cubs' official website. "It was a big game for us to win that game."

Chris Volstad (1-9, 6.28) is also hoping he can build on his latest outing.

Volstad allowed three hits and three walks in 6 2-3 innings of Sunday's 5-0 win over Colorado, snapping a 24-start winless streak for his first victory since helping Florida beat Houston on July 10, 2011.

This will be the right-hander's first outing of the season versus the Giants, against whom he is 1-2 with a 2.67 ERA in four career starts.

Angel Pagan, San Francisco's hottest hitter with a .393 average in his last 13 games, is 1 for 13 lifetime against Volstad.

Hunter Pence has also been locked in, batting .467 with five RBIs in his last four games, and is 7 for 18 lifetime against Volstad.