LOS ANGELES -- Andrew McCutchen's home run in the first inning Sunday ended the Pirates' 18-inning scoreless streak, but it wasn't enough to avoid a fourth consecutive loss.

After the first two series of the season, the Pirates have found baserunners hard to come by. They have eight runs in six games on only 21 hits.

Part of that has to do with the pitchers the Pirates have faced. They opened the season against the Chicago Cubs' Jeff Samardzija, who struck out 13 Sunday after dominating the Pirates on opening day. They faced two former Cy Young winners Friday and Saturday in Zack Greinke and Clayton Kershaw, and Kershaw may be the hottest pitcher in baseball.

Manager Clint Hurdle said the Pirates need to walk a fine line between understanding they faced elite pitching and eliminating their mistakes.

"The thing you also got to do is, you can't stick your head in the sand," Hurdle said. "You run through some at-bats and you see pitches that you had to hit, and you don't hit them.

"Let's be real, let's tip our cap when appropriate, but at the same time let's make sure we're doing everything we can to control our strike zone."

Several major contributors found themselves in early slumps after the first two series. Neil Walker is 0 for his past 15 at-bats, and Pedro Alvarez and Russell Martin are 0 for 14.

Alvarez struck out seven times in 10 at-bats against the Dodgers. He faced two left-handed pitchers in Kershaw Saturday and Hyun-Jin Ryu Sunday.

"We've invested in this young man," Hurdle said. "When you see him hot ... he can carry a ballclub. He can hit left-handed pitching. That's one of the challenges in front of him, though, is to hit premium left-handed pitching. You got to get him out there, you want to keep him in play."

"He's like a lot of us right now. We've got more work to do."

As a team, the Pirates have a .119 batting average, .188 on-base percentage and a .159 slugging percentage.

"[The runs] are going to come," Hurdle said. "We've got talented guys that can hit and have proven they can hit.

McCutchen, who hit the Pirates' first home run of the season Sunday, echoed Hurdle's lack of concern after six games.

"Continue to battle, continue to keep fighting," McCutchen said. "The pitching is doing a great job. We just got to keep going."

The Pirates also entered Sunday with fewer walks than every team in the National League except the Chicago Cubs.

The Pirates record doesn't reflect it, but their pitching staff has excelled in the first two series of the season.

A 6-2 loss Sunday to the Los Angeles Dodgers was the first game in which an opponent scored more than three runs. The Pirates allowed 10 runs in their first five games.

The starting pitchers have allowed 12 earned runs in 352/3 innings, good for a 3.03 ERA. The staff had a 2.82 ERA after Sunday. Entering Sunday, their 2.09 ERA ranked second in the NL behind the Dodgers (4-2).

In the Pirates' previous five games against the Arizona Diamondbacks at Chase Field, they hit .283 with six home runs and 18 runs. They are 3-2 in those games.