Rockies pitcher Ubaldo Jimenez struck out five hitters in 7 1/3 scoreless innings against the Nationals on Thursday. It was his first start since he tossed a no-hitter against the Braves last Saturday. Jimenez improved to 4-0 and his ERA fell to 0.95. "You know what an ace of a staff does?" manager Jim Tracy said. "He goes out there and performs in the manner in which you've seen this man perform this year. I would say 7 1/3 innings of scoreless baseball is a pretty good day's work toward helping your team win a baseball game."