Simontacchi, who missed the first month of the season with a groin injury, rebounded from one of his worst outings of the year to win for the first time in three starts. He allowed six hits, struck out two and walked one. The right-hander (3-4) allowed four earned runs in 4 2/3 innings on Sunday.
In addition to constantly getting ahead in the count, Simontacchi said it was the best command of his fastball he's had all year. But that wasn't his only pitch that kept Minnesota hitters off balance much of the night.
"I found my curveball again today," he said. "I was throwing that pitch pretty good, but everything goes off my fastball."
Manager Manny Acta said the curveballs were as sharp as Simontacchi has had all year.
His lone mistake was a three-run homer by Jason Kubel in the seventh.
"I shook off my catcher," Simontacchi said, laughing. "He called a changeup, and I wanted a fastball away. I threw the ball right down the middle of the barrel."
Acta, who gave Simontacchi a vote of confidence after his rough last start, was especially pleased.
"He did outstanding because our bullpen really needed a lift today," Acta said. "We didn't have our closer, and we'd didn't have [Jesus] Colome, so he gave us a huge, huge lift."
Both Colome and Chad Cordero had pitched the last three games, and Acta had no plans to use either one.
Much of Minnesota's offensive success this season has been by playing small ball. Instead, it was the Nationals using the method to manufacture runs. It was the fifth time in eight games that the Nationals had at least 11 hits and third time with at least 14.
The Nationals used 10 hits in the first four innings to take a 7-0 lead. Just two of those hits were for extra bases against Carlos Silva (3-7), who struggled to keep his pitches down.
After hitting the first pitch of the game for a single, Guzman scored on an RBI single by Zimmerman, and Church scored in the second after leading off the frame with a double.
For Guzman, it was the happiest of homecomings. He spent six years with the Twins before signing with Washington before the 2005 campaign.
"Everywhere I go I want to play well, not just because I'm here in Minnesota," he said.
Guzman is 20-for-39 in his last nine games. Friday was the second time in eight games he has gotten four hits.
"We have sometimes where we have one week you can do it better, and then you can come and do nothing," he said. "That's the game."
Ronnie Belliard, starting at second base in place of Felipe Lopez, made two tough plays on hard liners to start the game, including reaching to his left and spinning to throw out Joe Mauer. Simontacchi also started a 1-4-3 double play to end a Twins threat in the second.
Following the clutch double play, the Nationals scored twice in the third with two outs.
Zimmerman singled and advanced to second on a balk by Silva. He scored on a bloop single by Young. After a walk to Austin Kearns, a single by Church was just out of the reach of shortstop Jason Bartlett, scoring Young.
Young, a career .320 hitter in the Metrodome, is hitting .515 (35-for-68) with 19 RBIs in his past 20 games.
"It was good that everybody chipped in," Church said. "We just took advantage of the situations. We've had ample times where we've had guys on base but couldn't get that key hit. It seemed like tonight it was one after another, and we kept forcing the issue."
Guzman and Zimmerman had RBI singles in the fourth inning, and Young had an RBI single in the sixth for an 8-0 lead. That gave Acta reason to think he could have an easy final innings.
"I thought I was going to have the night off before Kubel hit that home run," Acta said. "Then my night off went out the window because this is a ballpark where a lot of things can happen, especially with this type of team. They're very energetic and athletic."
Back-to-back singles against Billy Traber got Minnesota within 8-4 in the seventh, but Saul Rivera allowed only one run in the final 1 1/3 innings.