Chicago coach Scott Skiles talks with players Ben Gordon, left, and Kirk Hinrich, right. Gordon and Hinrich are part of the 'Baby Bulls' group that has matured and defeated defending champion Miami in the first round of the NBA playoffs.

DEERFIELD, ILL. ? Chris Duhon thought back to his rookie season and all those substitution buzzers after his mistakes. He couldn’t take three steps in practice without coach Scott Skiles saying something, either.

And now?

He can smile. The former “Baby Bulls” look like a mature group now. A team that had not advanced past the first round of the playoffs in nearly a decade swept defending champion Miami after winning 49 games in the regular season. Next up: Detroit.

“Now that we’ve all matured and we understand how to play the game a lot better, he can relax a little bit,” said Duhon, a second-round pick from Duke in 2004. “He doesn’t have to be on us 24/7.”

Skiles a softy?

Not exactly.

Although Skiles said he hadn’t changed much during the past three or four years, the dynamic between the coach and his core of young players is a bit different these days.

“He’s loosened up,” Ben Gordon said.

There’s a trust, the kind born over time. Core players such Gordon, Luol Deng, Kirk Hinrich, Andres Nocioni and Duhon understand what Skiles wants, and they know each other’s tendencies.

They came of age together and experienced a major breakthrough in the first round, after losing in six games to Washington and Miami the previous two years.

The Bulls made a splash in the offseason, when they signed center Ben Wallace to a $60 million contract, and the younger players made waves during the season.

“I think you saw this year that Scott trusted Ben Gordon, Luol, Kirk much more,” general manager John Paxson said. “I think that’s just a natural component of that.”

Deng proved he’s an emerging star, averaging 18.8 points and 7.1 rebounds while shooting 51.7 percent, and Gordon led the Bulls with a career-high 21.4 points per game. Against the Heat, the two were even better.

Deng averaged 26.3 points and Gordon 25.5 as the Bulls won a series for the first time since 1998, when Michael Jordan and Scottie Pippen led them to their sixth title in eight years. It was a crucial step for a franchise that endured several rebuilding plans in the interim, and for a young core that seemed to be on the verge of a breakthrough.

Things began to fall into place after Paxson replaced Jerry Krause as general manager in April 2003.

He drafted Hinrich with the seventh pick that year and hired Skiles in late November, and three more important pieces came after a 23-win season. Paxson took Gordon with the third pick in 2004 and acquired the draft rights to Deng, then signed Nocioni from the Spanish League that summer.

The Bulls started the next season 0-9 but won 47 games, got back to the playoffs and took a 2-0 lead over Washington in the first round before losing the next four. A year later, after winning 41 games, they pushed Miami before losing in six.

“They earned their spots,” Skiles said. “Out of necessity they played very well. They’ve gotten better. They were also humbled for two years in the playoffs. They learned valuable lessons early on about how you have to compete, how hard you have to play to win a series.”

And now, their coach can lay off – a little.

Skiles lit into his team only “a handful” of times this year, because he no longer feels he needs to come down hard on this group. When they were 3-9, Skiles figured the Bulls would turn it around – and he kept that faith when they lost five of the first six games in January.

“They brought it here every day,” Skiles said. “As long as teams are doing that, you feel like it’s going to turn around, things are going to get better.”