BOSTON -- Throughout the A's impressive 2018 run to the postseason, it almost seemed like they were immune to losing streaks. But over the past couple of weeks, they find themselves in a funk, one that continued in Tuesday's 5-1 loss to the Red Sox.

Oakland's losing streak now sits at five games, the longest for the A's since dropping eight in a row from Aug. 28-Sept. 5, 2017. The loss to Boston was also their eighth in the past 11 games.

"We've got a little funk going on right now, across the board," Oakland manager Bob Melvin said. "Haven't played great defense, haven't pitched very well or swung the bats very well. But we'll come out of it. It's just a part of the season that's difficult, and you have to remain positive. These guys will."

Aaron Brooks shut the Red Sox down over six scoreless innings in his first start against them on April 1, but things went completely different in his second go. Brooks dug the A's into a hole early, surrendering a solo homer to Mookie Betts in the first.

It was the right-hander's shortest outing of the season as he lasted only 4 1/3 innings, allowing five runs (four earned) on six hits with three walks and two strikeouts. Brooks has allowed five runs in three of his past five starts.

"His stuff looked OK, but that's a pretty good hitting team and when you leave balls in the middle of the plate," Melvin said, "they're going to make you pay for it. I think that's what happened tonight for him."

It would have been a tall order to ask Brooks to match the performance from his counterpart on the mound. Oakland's bats struggled to get anything going against Boston starter Rick Porcello. The A's never had a runner get past second base against the right-hander, as he made life difficult for them with eight shutout innings, allowing just two hits and two walks with eight strikeouts.

"He was off to a little bit of a rough start, but it didn't look like it tonight," Melvin said of Porcello, who entered the night with a 7.43 ERA in five starts. "Used all of his pitches, and it looked like he was pretty fine on the corners. I came [into the clubhouse] to look some up, and they were literally right on the corner. Just enough breaking stuff to keep you off speed. He pitched a really good game."

Robbie Grossman broke up Boston's shutout with a homer in the ninth, his third long ball of the season, but Red Sox reliever Tyler Thornburg shut the door.

With the loss on Tuesday night, the A's (14-18) finished April with a record of 11-15, their first losing record over a full month since August 2017, when they went 11-16.

Do April showers bring May flowers?

Matt Chapman, who is emerging as a team leader in only his second full season in the Major Leagues, held court inside Oakland's clubhouse following the loss. His message: New month, new team.

"This month didn't exactly go the way any of us wanted it to, but that's baseball, and I think that our team is pretty resilient," Chapman said. "We've had the tendency to start slow and then pick up the pace and get hot at the end. We did it last year."

The A's hovered around .500 at the end of April 2018, finishing that month at 13-12 and five games out of first place in the American League West. One year later, it's the same scenario -- five games behind the Astros for the AL West lead.

So how does Oakland turn this around?

"You have to just keep working hard and stay positive," Chapman said. "With the whole Japan trip and everything, it seems like it's been a long year already. But it's only the first month, and there's so much baseball left. We're still battling. I just came in and said, 'April is behind us. Don't let the A's get to May.' Tomorrow is May 1, and we can turn over a new leaf and get back to work. Just start off fresh and treat it like a whole new season."

2018 vs. '19
The A's had a surprisingly effective starting rotation in 2018, but their true strength came from great defense, a shutdown bullpen and a propensity to crush homers.

In 2019, those three phases have not measured up.

Here's a comparison at some of the key team stats for Oakland and where the A's ranked in the Major Leagues from the end of 2018 to where they stand in '19:

Defensive Runs Saved
2018: 61 (3rd in MLB)
2019: 1 (19th in MLB)

Bullpen ERA
2018: 3.37 (3rd)
2019: 4.27 (18th)

Home runs
2018: 227 (3rd)
2019: 42 (7th)

The power and fielding numbers in recent weeks have been particularly concerning. Since April 12, the A's have hit 11 home runs, the least of any team in the Major Leagues.

Oakland has also committed 16 errors in its last 19 games after just three in its first 13 games.

Starters have not been great; the staff entered the night with a 4.87 ERA. But if things are going to turn around for the A's, they will need to count on their true strengths.

"Home runs are definitely a big part of our game, and the offense feeds off itself," Chapman said. "We haven't been able to get that big hit or home run, but I know that stuff is coming. We're good enough to not rely on the homer, but that is our strong suit."

Moreland is a problem
If it seems like Mitch Moreland always homers against the A's, it's because that is actually somewhat accurate.

Moreland launched a two-run homer off Brooks in the fourth to put the Red Sox ahead by four. It was Moreland's 21st career home run against Oakland, six more homers than he's hit against any other opponent, and also tied with Albert Pujols for fifth most among active hitters against the A's.

Moreland has now homered at least once against Oakland in nine of his 10 Major League seasons.