WASHINGTON -- Over his time as a player and manager, Dave Roberts has been around a lot of international players who have come over to the Majors with plenty of experience and expectations.

Some have responded well right away, quickly establishing themselves in the Majors. Others have taken some more time. Then there’s always the cases of international signings just not working out as both sides hoped.

In Yoshinobu Yamamoto’s case, Roberts described the right-hander as “being in the middle” through his first five starts in the Majors. On Thursday, however, the Dodgers finally got to see what it looks like when Yamamoto is at his best after the Japanese right-hander tossed six scoreless innings and struck out seven in the Dodgers’ 2-1 win over the Nationals at Nationals Park.

“So far up to this point, yes,” Yamamoto said through interpreter Yoshihiro Sonoda. “That was the best [start in the Majors.]”

The first five starts of Yamamoto’s career had a wide range of outcomes. His first start in Seoul, South Korea, was just about the worst possible way Yamamoto could’ve hoped for his debut to go. In that start, Yamamoto allowed five runs and recorded just three outs.

Yamamoto’s next two starts, however, started to show all the signs of the pitcher every team wanted this offseason. He tossed five scoreless frames against both the Cardinals and Cubs, showing the Dodgers some mental fortitude and ability to bounce back after a bad start.

But just when the Dodgers thought Yamamoto was hitting his stride, his next two starts were just average. He gave up three runs over five innings against the Padres and then four runs (three earned) against the Mets over six unconvincing innings.

A lot of the reasons for Yamamoto’s up-and-down start to the season have been his inability to possess all three of his pitches in a particular start. On Thursday, he had the four-seamer, curveball and splitter all working, making it tough on the Nationals.

“It was probably his best start he has had with us,” Roberts said. “And actually, the last two have been really good.”

The four-seam fastball, in particular, has been a struggle for the Japanese right-hander. The scouting report coming out of Japan was that controlling and commanding the fastball was the key to Yamamoto’s success.

Against the Nationals, Yamamoto threw his four-seamer 40 times. While he only got two swing-and-misses, he did get 15 called strikes on the pitch. The average exit velocity against it was only 81.1 mph. Misses over the heart of the plate were almost nonexistent for Yamamoto, opening the door for the curveball and splitter to be devastating to opposing hitters.

Yamamoto threw the splitter and curveball 26 times apiece, getting a combined seven whiffs on the pitches. There perhaps wasn’t a better curveball than the one he threw to Jesse Winker on a 3-2 count to freeze the power-hitting outfielder in the sixth inning.

“He pitched very well,” said Nationals first baseman Joey Meneses. “He has great command of the zone and he’s got great pitches. Obviously, we were unable to do anything off of him today.”

When his four-seam fastball is on and located well, Yamamoto is tough to hit. When it’s not, it has resulted in a lot of hits and some home runs.

“I saw his fastball in the bullpen today, and I thought it was going to be a good day,” said Dodgers catcher Austin Barnes. “He came out today and was a little bit more crispy. I thought he executed it pretty well throughout the game, and it was a big pitch for us in big situations.”

In the fifth inning, Yamamoto had a scary moment when Eddie Rosario hit a 104.8 mph liner back to the mound. Yamamoto had a split second to react to the ball, which was on a direct path to his face. But he was able to make a spectacular catch, showing off his reflexes.

After the play, Yamamoto turned to Roberts and cracked a smile.

“He said he almost died,” Roberts shared. The sense of humor reflected everything the Dodgers have been saying about Yamamoto off the field. Now he’s starting to put things together on the bump, posting a 2.00 ERA since his debut in South Korea.

“I think that these last two shows that when he executes his pitches, he can get anyone out,” Roberts said. “I expect this to kind of dovetail into more confidence."