MONTREAL (Ticker) -- After a rare offensive outburst, the Montreal Expos ran into Joe Kennedy .

Kennedy allowed only one hit in six innings as the Colorado Rockies posted a 2-0 win over the Expos, who were denied their first three-game winning streak of the season.

Saddled with the worst record in the major leagues at 7-21, Montreal routed the Rockies, 10-4, Tuesday in its biggest output of the season.

"I felt strong and good and it showed," Kennedy said. "Command-wise with the fastball and slider, it was my best game. I kept them off balance and was able to throw the ball where I wanted."

Pinch hitter Mark Sweeney provided all the offense Kennedy, the Rockies' hottest pitcher, needed with a two-run double off Zach Day in the seventh inning.

The hit made a winner of Kennedy (4-0), who gave up just a single to Juan Rivera in the second. He walked two and struck out six while lowering his ERA to 2.23.

"I knew he was pitching a great game, a one-hitter," Sweeney said. "If no one's on, he's hitting there."

The Expos threatened after Kennedy left, stranding seven runners in the last three innings. They loaded the bases with one out in he eighth off Brian Fuentes , but Vladimir Nunez worked out of trouble by getting Tony Batista to pop up and Brad Wilkerson to fly out.

In the ninth, Shawn Chacon gave up singles to Rivera and rookie Terrmel Sledge , but Andy Fox struck out after failing to get down a bunt. Chacon also struck out pinch hitter Matt Cepicky , then got Endy Chavez to line out to left fielder Matt Holliday , securing his seventh save.

"We didn't take advantage of the opportunities we had," Expos manager Frank Robinson said. "Kennedy had pretty good stuff out there. He had a very good breaking ball and a sneaky fastball. But we had opportunities and we just didn't get hits at the right time."

Day (2-3) matched Kennedy until the seventh, when he gave up a one-out double to Holliday. With the pitcher's spot up next, the Expos intentionally walked fellow rookie Brad Hawpe .

Looking for offense, Rockies manager Clint Hurdle went to his bench and the move paid off as Sweeney doubled to deep center field.

"We've got a pitch count and our guy was pitching on three days' rest," Hurdle said. "If we went three-up, three-down, we would have sent him back out there and stretched one more inning out of him."

"Day didn't give me too much to hit on that at-bat," Sweeney added. "I was trying to see a strike and drive the ball. I was hoping for something elevated."

Day pitched well enough to win, scattering seven hits in seven innings.

"There's pressure," Day said. "You get one hit and you pitch around a guy because one run might win the game. It's (lack of offense) tough, but you try to battle through it."