The Arizona Diamondbacks have been surprising on the strength of their starting rotation, but their bullpen remains a concern.

The D-backs hope for better late-inning results when they open a four-game series against the host Los Angeles Dodgers on Monday night.

Arizona's beleaguered bullpen faltered again on Sunday, when Ian Kennedy allowed the go-ahead run in the ninth inning of a 3-2 loss to the Chicago Cubs.

The D-backs will look to bounce back against Los Angeles, which rallied with two runs in the ninth on Sunday to beat the Philadelphia Phillies 5-4 and snap its four-game losing streak.

Dodgers outfielder Mookie Betts led the charge by going 2-for-4 with a home run and two RBIs.

Betts has hit safely in 16 of his last 20 games, batting .294 (25-for-85) with seven homers, 14 RBIs and 22 runs scored over that stretch.

"I think just the mental side of it has been the biggest difference," Betts said. "Just being more positive. Looking for the next opportunity instead of dwelling on the last one. And just trying to enjoy each and every day."

The series will feature the top two starting rotations in the majors in Los Angeles (2.45 ERA) and Arizona (2.51).

The D-backs' starting pitchers are 8-0 with a 2.00 ERA over the last 15 games, but closer Mark Melancon has an 8.49 ERA with five losses.

Kennedy entered a tie game on Sunday and promptly yielded a leadoff double in the ninth before Chicago's Frank Schwindel delivered a go-ahead single.

D-backs manager Torey Lovullo acknowledged that changes might be needed in the bullpen.

"We're mindful of everything that's happening, we're all having discussions about what's going to put this team in the best position to win baseball games, and those discussions will continue to be had over the course of the next couple of days," Lovullo said.

Arizona will begin the series with left-hander Madison Bumgarner (2-1, 1.78 ERA), who settled in after a shaky start and pitched 6 1/3 strong innings in a 9-3 victory over the Miami Marlins last Tuesday.

Bumgarner, 32, allowed two earned runs with five strikeouts and one walk while throwing a season-high 96 pitches.

Bumgarner's 1.78 ERA is the lowest in his career through seven starts, ahead of his 2.31 mark in 2013.

Chris Taylor is 3-for-25 with 11 strikeouts against Bumgarner, who is 15-15 with a 2.77 ERA in 38 games (37 starts) vs. the Dodgers.

Los Angeles will counter with right-hander Tony Gonsolin (3-0, 1.33), who allowed one hit over five scoreless innings in an 11-1 victory over the Pittsburgh Pirates last Tuesday.

Gonsolin, 28, has limited the opposition to a .168 batting average through his first six starts covering 27 innings.

"I've just been trying to throw my best pitches," Gonsolin said. "Trusting my stuff, trusting my defense is going to make a play, and not trying to avoid contact or anything like that. Just kind of seeing what happens."

The California native made his major-league debut against Arizona in 2019 and is 2-2 with a 3.70 ERA in 10 games (nine starts) against the D-backs.

David Peralta is 2-for-15 against Gonsolin while Christian Walker is hitless in 10 at-bats.