MIAMI -- It's been pretty much smooth sailing for Marlins rookie Sandy Alcantara since rejoining the rotation in September. But on Tuesday, the right-hander ran into control troubles on a night he needed to be sharp, facing off against Stephen Strasburg.
Alcantara labored through four innings, allowing three runs while walking a career-high six, and the Nationals, behind Strasburg's 11 strikeouts in six innings, held on for a 4-2 win over Miami at Marlins Park.
"When we talk about young guys, I think this is what we see," Marlins manager Don Mattingly said. "We see good and we see ones that are not as good. Today, obviously, the command wasn't there for Sandy. A lot of misses. The counts get bad. Just a lot of pitches in a short period of time. It's something he will learn from, and you've got to continue to work and be consistent with what you do.

"That's what separates guys who are going to be really good, and guys who are going to be OK. It's that consistency. You expect it from younger pitchers. Hopefully, we're just learning all the time."
Alcantara fell to 2-1 with a 2.35 ERA in four big league starts, with three coming in September. The 23-year-old had allowed two runs in 14 innings in his previous two starts this month.
"I tried to do my best and tried to help my team the best I could," Alcantara said. "I understand that happens in the game. That happens with everybody. For me, I don't know what happened tonight. I tried to keep the ball down. I just missed too much on my arm side."
Anthony Rendon had two RBIs, and Bryce Harper walked five times, one shy of the Major League record he tied in 2016, for the Nationals, who salvaged a two-game split.
Peter O'Brien, who is making the most of an opportunity to play as a September callup, connected on a home run off Strasburg in the second inning. It was his third home run.
"It was great," said O'Brien, who attended the University of Miami. "It was nice to get that first one on the board and get a little momentum on our side."
For Alcantara, Tuesday was his first rough start of the month. Ranked by MLB Pipeline as Miami's No. 2 prospect, the rookie had difficulty working both sides of the plate. Of his 91 pitches, just 46 were strikes.
Alcantara scattered six hits, and struck out three, but had trouble missing bats. He induced just six swinging strikes, with five of them on 30 sinkers.
Alcantara ran into difficulty in the first inning, issuing a leadoff single to Adam Eaton, and he had the bases full with one out. Yet, he logged two strikeouts in the inning, and escaped without allowing a run.

But in the second inning, the Nationals capitalized on a leadoff walk to Matt Wieters. Eaton eventually drove in Wieters with a single to open the scoring, and Trea Turner's squeeze bunt drove in the Nats' second run of the frame.
O'Brien's home run to lead off the second inning closed the gap for Miami to 2-1.
But in the fourth inning, Alcantara's last, he yielded two walks, including one to Eaton, and a sacrifice fly to Rendon.
Strasburg didn't allow Miami much, and improved to 17-7 in his career against the Marlins. At one stretch, he fanned six straight. Miami's second run came on J.T. Realmuto's RBI single in the fifth inning.
"Peter hit the homer and made it 2-1," Mattingly said. "By the fourth, you feel like you're just getting destroyed, because Strasburg is really rolling. His pitch count is way down. We're throwing a ton of pitches, and we're right in the game."
MOMENTS THAT MATTERED
After the Marlins pulled within a run at 3-2 in the fifth inning, the Marlins mounted a two-out rally, which started with a JT Riddle single and a single by Miguel Rojas. Realmuto delivered an RBI single, and O'Brien walked to load the bases. Brian Anderson ran the count full, but struck out against Strasburg. The Nationals tacked on an insurance run in the sixth inning.

"We kind of hang in there in that game," Mattingly said. "It was one of those things where we hung around long enough, and we've got a shot to win this thing."
SOUND SMART
Reliever Tayron Guerrero, who had a strikeout in a clean fifth inning, has allowed three earned runs in his last 16 2/3 innings (1.62 ERA) at Marlins Park.
YOU GOTTA SEE THIS
O'Brien has shown power to center and right-center since being in the lineup. But his home run on Tuesday was pulled to left field. Statcast™ tracked the drive at 362 feet with an exit velocity of 97 mph. It was a towering shot with a launch angle of 37 degrees.

"I think the biggest thing is I feel ready," said O'Brien, who is back in the big leagues for the first time since 2016. "I prepared myself for this, that's what the last couple of years really taught me, to be ready, stay hungry and maximize every opportunity."
HE SAID IT
"What's been impressive in talking with him in his at-bats, you can tell he has a plan. He wants to stick with what he can do up there, and he has some feel for what the pitcher is doing. He has a plan with what he wants to do with that. It's different when you see some of our guys, it seems they are getting out of sorts, without a true plan. You look at Peter, and you can tell he has a plan." -- Mattingly, on O'Brien, who is hitting .308 with three homers as a September callup
UP NEXT
The Marlins close out their home schedule with a four-game series with the Reds, beginning on Thursday at 7:10 p.m. ET. Jeff Brigham (0-2, 7.36 ERA), a rookie who will make his third big league start, gets the start for Miami. Brigham has logged 7 1/3 innings with the Marlins after posting a 2.36 ERA in the Minors. Lefty Cody Reed (0-2, 4.32) goes for the Reds.