CHICAGO -- Starter Jason Hammel's third inning cramp turned into an opportunity for Travis Wood and the Chicago Cubs bullpen on Monday.

Wood (3-0) rode to the rescue and pitched four perfect innings in relief for a victory as he led the Cubs to a 2-0 decision over the Los Angeles Dodgers in the first in a four-game series.

Three other relievers were just as tough over three no-hit innings.

"It was truly Travis Wood's day," Cubs manager Joe Maddon said. "He set that game up, period. He was so pitch-efficient, he permitted us to do what we did. Four innings, 43 pitches. He was spectacular."

Jason Heyward delivered a go-ahead RBI single as the Cubs ran their winning streak to six games. Heyward was 1-for-4 with an infield hit that scored Ben Zobrist in the fifth to break a scoreless tie.

Wood got the emergency call in the third inning after Hammel experienced cramping in his right hamstring as he warmed up.

Wood went on to pitch four hitless and scoreless innings and struck out four. Five Cubs pitchers collectively held the Dodgers to just one hit.

"Nothing prepares you for it, at least they give you as much time as you want to make sure you're loose," Wood said. "But we played a great game through and through and our bullpen nailed it today."

Cubs closer Hector Rondon worked a one-two-three ninth with a pair of strikeouts for his ninth save of the season.

Dodgers starter Alex Wood (1-4) suffered the loss after working five innings and allowing two runs.

Chicago improved to a Major League-best 35-14 and moved a season-high 21 games over .500. Los Angeles (27-25) saw a two-game winning streak snapped.

The Cubs loaded the bases with one out in the second but came up empty as Hammel struck out looking and Zobrist struck out swinging on a 2-2 pitch.

Hammel came back out to pitch but found it difficult to continue after several warmup tosses from the mound while Maddon watched closely.

"When a pitcher hurts his leg, the next thing he hurts is his arm," Maddon said. "So we had to get him out of there."

Maddon said Hammel appears likely to pitch in his next scheduled start later this week. Hammel, meanwhile, said he felt fine after the game.

"Obviously I want to see how it feels tomorrow," Hammel said. "But I feel fine right now."

Wood, a former Cubs starter and now middle reliever, entered and struck out two of three batters in a one-two-three third en route to his four-inning outing.

But the Dodgers still thought they might have an opportunity against the Cubs bullpen.

"Once Hammel goes out of there and we're in the bullpen in the third inning you're thinking you can try to grind some at-bats and wear out the bullpen," said third baseman Justin Turner, who had the Dodgers' lone hit. "But he (Travis Wood) did a good job of pounding the zone and getting some quick outs."

The Cubs broke the shutout with two fifth inning runs.

Zobrist opened with a single to right and quickly sprinted to third after Yasiel Puig's bobble sent the ball to the wall. Zobrist came home Heyward's infield single.

After Kris Bryant struck out, Heyward scored on Anthony Rizzo's double to right with one out for a 2-0 lead.

The Dodgers' Wood was pulled for a pinch hitter in the sixth. He allowed seven hits, walked three and struck out seven while giving up two earned runs.

NOTES: The Dodgers have beaten the Cubs in four straight season series since 2012. Los Angeles and Chicago split last year's four-game Wrigley Field leg last year. ... LHP Clayton Kershaw's 10 strikeouts on Sunday made him the first big league pitcher to hit 100 strikeouts in a season while walking just five. ... LHP Alex Wood, Monday's Dodgers starter, was supposed to Friday in New York but had his start pushed back three days due to triceps soreness. ... Cubs 2B Ben Zobrist, one of the Cubs hottest bats this month, led off on Monday in place of Dexter Fowler, who was out with a sore right heel. ... Fowler is second in the big leagues with a .433 on-base percentage. He has hit safely in 29 of his last 35 games and is fourth in the NL with 15 doubles. ... RHP Jake Arrieta (9-0, 1.72 ERA) faces Dodgers LHP Scott Kazmir (4-3, 4.84 ERA) in Tuesday's second game. Arrieta leads the majors with a .168 opponents' batting average and is second with is 1.72 ERA. The Cubs have won his last 23 starts, including his no-hitter against the Dodgers on Aug. 20, 2015.