BOSTON — Red Sox manager Alex Cora has been proclaiming recently that he didn’t think his team was far from putting good baseball together following a dismal stretch of games.

Those days of optimism appear to be dwindling after Boston’s latest setback.

The Red Sox lost their 17th one-run game of the season on Tuesday, this time falling 4-3 to the Los Angeles Angels in 10 innings filled with missed opportunities, poor execution defensively and another inconsistent night from the bullpen. It was their eighth loss in 10 games. They are now 9-10-1 in series play, including 4-5-1 at Fenway Park.

“We keep making the same mistakes. We’re not getting better,” Cora said after the game. “At one point it has to be on me I guess. I’m the manager. I’ve got to keep pushing them to be better. They’re not getting better. They’re not. We keep making the same mistakes. I’ll be honest about it and very open about it.”

Tuesday’s loss came a night after Boston also lost by a run to an Angels team that had lost seven of eight and three consecutive series.

The game started out with some promise.

Starting pitcher Brayan Bello pitched a scoreless first to snap a four-game streak of Boston pitchers allowing at least one run in the opening inning.

But then the Angels took a 3-0 lead in the third inning via an RBI single by Zach Neto and a two-run single by Nolan Schanuel.

Boston got one run back during its half of the inning but failed to close the gap more despite having runners on second and third base with no outs.

The Red Sox outhit the Angels for the second straight game. But also committed three fielding errors.

“You get frustrated, but at one point, OK, what are you going to do? What’s going to change? We keep doing the same thing,” Cora said.