WASHINGTON -- Washington Nationals starter Jordan Zimmermann won his 10th game of the season, and Adam LaRoche had three hits and was part of two rallies as the Nationals beat the Colorado Rockies 5-1 on Thursday.
Zimmermann (10-3) is now 4-0 lifetime against the Rockies as he allowed just six hits in a showdown against veteran right-hander Roy Oswalt, who was making his Rockies debut.
Zimmermann fanned nine batters with one walk and threw 112 pitches (85 for strikes) before being lifted for a pinch-hitter in the last of the eighth.
It was the fourth loss in a row for the Rockies (37-37), while Washington (36-36) is back at .500 after losing four of the last six prior to Thursday.
Rafael Soriano came in to pitch the ninth for the Nationals.
Zimmermann, who allowed one unearned run in eight innings, helped his own cause with a sacrifice fly in the sixth to make it 5-0.
Colorado finally scored in the eighth against Zimmermann on a RBI single by DJ LeMahieu after rookie second baseman Anthony Rendon made a throwing error on a groundball off the bat of Tyler Colvin.
Before the game Washington manager Davey Johnson compared Oswalt and Zimmermann.
"They both basically come at you with a fastball," he said. "Oswalt pitches more up in the zone than Zimmermann. They are both aggressive coming after you."
The first 10-game winner in the National League was Adam Wainwright of the Cardinals.
LaRoche gave the Nationals a 5-0 lead in the fifth when he hit a two-run triple to right center against swalt, who was making his first major-league appearance of the season.
Washington had taken a 2-0 lead in the fourth on a two-out single by Kurt Suzuki that scored LaRoche from second.
Ian Desmond had given Washington a 1-0 lead in the second with a one-out homer to left against Oswalt, who was 3-2 with a 2.16 ERA for the Rockies' Double-A Tulsa affiliate before he was promoted to the big leagues.
Oswalt was signed by the Rockies on May 3 and entered the game with a 7-5 career record against the Nationals and an overall major-league record of 163-96 with a 3.28 ERA.
Oswalt fanned six of the first 12 batters he faced but allowed nine hits and four runs in five innings with 11 strikeouts on 101 pitches before he was lifted for a pinch-hitter to begin the top of the sixth.
The last big-league appearance for Oswalt was October 2 at Oakland while with the Texas Rangers.
"He is not going to say a whole lot. That is refreshing. He will go out and compete the best he can," Colorado manager Walt Weiss said.
Zimmermann, who allowed no runs and three hits in the first six innings, has not lost at Nationals Park since May 2012, going 12-0 during that span.
NOTES: To make room for Oswalt, the Rockies sent LHP Jeff Francis to Triple-A Colorado Springs. "I am glad Jeff is still with us (in the system). He has meant so much to this organization," Weiss said. The Rockies also designated RHP Chris Volstad for assignment. ... Johnson said OF Bryce Harper, on the DL since early June with left knee bursitis, continues to make progress. "He ran in the outfield today. He will hit in the cage today. He is close" to starting a minor-league rehab assignment, Johnson said. ... Colorado RF Michael Cuddyer is a native of Norfolk, Va. and his wife, Claudia, graduated from Washington-Lee High in Arlington, Va., about 10 miles from Nationals Park. Cuddyer rented a suite for the game to mark their son Casey's fifth birthday. Cuddyer expected about 25 family and friends at the game. He singled in the first to extend his career-best hitting streak to 18 games.