CHICAGO -- The Chicago Cubs have found themselves a new phenom.

Make that an old phenom.

Three weeks removed from his 40th birthday, Greg Maddux is pitching like the ace of old. He's 5-0 for the first time in his illustrious career, and his miserly 1.35 ERA is second best in the majors.

Better yet, he's carrying a Chicago team that is above .500 despite injuries to starters Kerry Wood and Mark Prior and a rough start by Carlos Zambrano.

"Without his 5-0, we wouldn't be close to where we are," Cubs manager Dusty Baker said. "He's not gloating or reveling over what he's done, he just continues to do what he's doing."

The right-hander has been a model of quiet consistency his entire career. More crafty than overpowering, he's more likely to trip hitters up with darting pitches that paint the corners than a 98 mph fastball. He studies hitters with the intensity of a research scientist, and uses that knowledge to pick apart their weaknesses.

In 20-plus seasons, he's won 323 games, struck out 3,076 and has a career ERA of 3.00. He won four straight Cy Young awards, and went 17 years without a losing record.

"He just has a passion for the game," said Henry Blanco, who was Maddux's personal catcher for two years in Atlanta and now is in his second season with the Cubs.

"He knows hitters as well as anybody else, and I think that's what makes him so good," Blanco said. "He knows what it takes to go out there and win a ballgame. He's going to give you 100 percent every time he's on the mound."

Last year, though, he wasn't very Maddux-like. His 13-15 record and 4.24 ERA were his worst since 1987, his first full season in the majors. And he looked, well, like a guy easing toward middle age.

Though he's never been a workout fiend, Maddux always has been fit. But he was starting to look a little flabby.

"There's good years and there's bad years," Baker said. "There's great years and there's good years. There's fair years and poor years. ... He only had 15 [great years] in a row. Maybe it was time."

Mediocrity didn't sit well with Maddux. He worked with a personal trainer in the offseason, doing three or four 90-minute workouts a week with noted physical therapist Keith Kleven that focused on his core, leg strength and flexibility.