PHILADELPHIA -- He was 23 and had all of 17 Major League appearances behind him the last time these Colorado Rockies bullied their way into the postseason, but Colorado pitcher Ubaldo Jimenez was certainly not lacking in confidence.

Or, as it turned out, success.

Jimenez, who gets the start on Wednesday in Game 1 of the National League Division Series against the Phillies, had a 2.25 ERA in three postseason starts for the Rockies in 2007, the year Colorado stunned baseball with a late-season postseason push.

Jimenez allowed one run in 6 1/3 innings in an NLDS game against the Phillies that fall. He followed that by allowing one run in five innings in the NL Championship Series against Arizona. He finally buckled -- albeit a little -- in the World Series, allowing two runs in 4 2/3 innings against the Red Sox at Fenway Park.

To be sure, it was a tough spot for the right-handed Jimenez, now 25. But the pressure cooker of pitching in October never amounted to much more than a sweat for him. He thrived instead of wobbling.

"Probably, I was so excited that I didn't even know what I was doing," Jimenez said on Tuesday during a workout day for both teams at Citizens Bank Park.

Colorado third baseman Garrett Atkins, who has watched Jimenez develop from a hard-thrower with command issues into a pure pitcher, wasn't buying that for a minute.

"That situation can be extremely scary," Atkins said. "But when he faces guys, they're not very comfortable hitting against him. And nothing seems to faze him. He does not seem to get too rattled."

Tale of the Tape: Game 1 Starters
Rockies' Ubaldo Jimenez Phils' Cliff Lee
2009 REGULAR SEASON
Overall 33 GS, 15-12, 3.47 ERA, 85 BB, 198 K 34 GS, 14-13, 3.22 ERA, 43 BB, 181 K
Key stat 6 1/3 IP, 1 ER, 3 H, 5 SO, 4 BB, no decision vs. PHI in '07 NLDS 1.01 WHIP in five starts for Phils at CBP
2009 REGULAR SEASON
Career 3 G, 3 GS, 0-1, 2.25 First appearance
AT CITIZENS BANK PARK
2009 No games 5 GS, 3-2, 2.52
Career 2 GS, 0-1, 8.10 5 GS, 3-2, 2.52
AGAINST THIS OPPONENT
2009 regular season No games 1 GS, 1-0, 1.29
Career 2 GS, 0-1, 8.10 1 GS, 1-0, 1.29
Loves to face Carlos Ruiz, 0-for-3 Chris Iannetta 0-for-3, 3Ks
Hates to face Pedro Feliz, 3-for-4 Dexter Fowler 2-for-4, 1 2B
Why he'll win 9-3, 3.08 ERA since break 2.75 ERA in 11 starts made this yr. w/ 5 days of rest
Pitcher beware .304 batting average against in the first inning 2-4, 6.13 ERA, .331 opp. BA in last seven starts
Bottom line Make big pitch early Regain consistent command
*If necessary
All games on TBS

That was obvious enough during the regular season, as Jimenez went 15-12 with a 3.47 ERA while throwing a career-high 218 innings with 198 strikeouts, also a career high. Jimenez was 9-3 with a 3.08 ERA after the All-Star break, which rivaled anything that teammate Jorge De La Rosa did in that span (3.46 ERA, but a 10-2 record).

"He's had a very good year, but there is more of him to come," Colorado manager Jim Tracy said. "He's going to become a better pitcher than we've seen up to this point this season.

"Once he deals with not needing 100-plus pitches to get through six innings, I think it's safe to say we're racing toward developing quite a horse at the top of our pitching staff."

One who has certainly become more than a one-trick pony. While Jimenez has the best average fastball velocity of any pitcher in the Major Leagues (96.1 mph) -- he could always throw hard -- he is at his best when his sinker is moving. He's also cut his walks from 103 a year ago to 85 and with even more innings of work.

Now comes the challenge of the postseason again for Jimenez and the Rockies.

Pitching at Citizens Banks Park is a thorny proposition for any pitcher. The Phillies led the National League in home runs (224, or 34 more than the second-place Rockies), including a league-best 108 home runs at their home ballpark.

But consider that Jimenez allowed 13 home runs this season in 218 innings, putting him behind only San Francisco's Tim Lincecum (10 home runs in 225 1/3 innings), Kansas City's Zack Greinke (11 in 229 1/3) and St. Louis' Joel Pineiro (11 in 214).

"The lineup is a big challenge," said Jimenez, who admitted to being a little wary of the jackrabbits at the top of the Phillies lineup, Jimmy Rollins and Shane Victorino.

"Anybody in that lineup can hurt you, from the front-runners to the eighth hitter. It's a big challenge. It's a tough lineup, a really tough lineup. But there's nothing you can do. The only thing, I'm going to go out there and just pitch my game, try to win."

Really, that's all Jimenez has ever done, no matter the team, the circumstances or, as it showed in 2007, the stage.

"When I got to the mound, I was able to relax and just pitch my game and forget about the crowd, forget about everything else," Jimenez said. "Just focus on the hitters and just go out there and have fun."