As he does after every road game, veteran point guard Andre Miller sat quietly in front of his locker room stall wearing his all-black NBA sweatsuit after the Wizards defeated the Chicago Bulls, 75-69, on Tuesday at United Center.

The victory, however, was different than any other that Miller, 38, has experienced in 15 seasons in the NBA because he finally advanced to the second round. But you couldn’t tell from his subdued mood. When told that the Wizards’ four-games-to-one series victory ended Miller’s hold on the title of most regular season games in NBA history without ever making it to the second round (1,184), Miller asked, “In history?”

He then shrugged. The Wizards won a playoff series for the first time in nine years and gave Washington basketball fans  their third trip to the Eastern Conference semifinals since the 1970s but reacted to the accomplishment by playing it cool. Aside from a larger crowd of visitors to congratulate them — mostly the Monumental Sports and Entertainment ownership contingent and their family members — it felt like they had just played the 87th game of the season, not the clinching Game 5 of the first round.

“There’s nothing to celebrate yet. As I told our guys. Let’s move on now. Let’s see what we can do here,” Coach Randy Wittman said. “Again, a lot of it is going to be the same coach speak of, ‘let’s be greedy,’ moving forward here and seeing what we can do in the next round. There will be time to reflect at the end of the year.

“Obviously, it’s my first time in the playoffs as a head coach. I’m obviously very lucky to be in the playoffs the first time and to win a round for the first time out. But now is not the time for that.”

Wittman probably had the most animated reaction when he finished his postgame interview and spotted Wizards owner Ted Leonsis standing in front of the locker room. He smiled and gave his boss a hug while Leonsis told him, “Good job, Randy.”

Though he was making his debut against a former NBA coach of the year in Chicago’s Tom Thibodeau, Wittman helped his players establish a mind-set to never get complacent and to play desperate. But Wittman’s players also weren’t satisfied with just four postseason wins.

“It’s just first round. Fortunately, I know how it takes to be in the NBA Finals, and trust me: It’s not the same feeling yet. We’ve just got to go to another round,” said Marcin Gortat, who reached the Eastern Conference finals twice and the NBA Finals once with Orlando. “Let’s just not, let’s don’t get excited. We happy we won. Nobody predicted we were going to be in second round – but nobody predicted we were gonna be in playoffs. Nobody predicted we were going to be in second round. Let’s just take it day-by-day and game-by-game and we’ll see where we can go. We are good team. We believe in this. If we play really hard and we are really physical, we can beat everybody. We proved that.”

Trevor Ariza hasn’t won a playoff series since winning a championship ring with the Los Angeles Lakers in 2009, but getting that taste again has only made him hungrier. The Wizards now await the winner of the Indiana Pacers-Atlanta Hawks series.

“A big step. Definitely a big step for our organization. It’s been a while since we even been in the playoffs and to win a playoff series is huge. But that’s not all we’re trying to do,” Ariza said. “There’s still more to go, still more basketball to be played and we’re going to sit and watch the other series and see who we play next.”

Miller had made it to the playoffs with all-stars Carmelo Anthony, Brandon Roy and Andre Igoudala (on two different teams) a total of nine times in the previous 10 seasons with Denver, Philadelphia, Portland and Denver again. But he had to wait for his 10th trip, on a team led by playoff novices John Wall and Bradley Beal – and with a franchise that has had little playoff success in his lifetime – to finally end up on the right side of a close out game.

“I’m just happy to be in this position,” Miller said. “Tough series. A grind out series for both teams. Young guys played big. They did a great job. they just went out and played basketball. They didn’t make a lot of mistakes, they just played good basketball. They just played solid the whole series.”

A trade deadline pickup from Denver, Miller played a huge role in helping the Wizards qualify for the playoffs by providing the team with a quality backup for a Wall and a play maker to help Beal develop as a scorer. He scored eight points in the fourth quarter of Game 1 to set the table for an impressive five-game run through the Bulls.

In the closeout game, Miller had little success, going scoreless in 11 minutes. But Wittman still put him in the game late to help handle the Bulls’ full-court press and Miller drew a foul. Miller missed both free throws and angrily swung at the floor, without even realizing that Nene had batted the offensive rebound out to Beal.

In just his second season, the 20-year-old Beal – who was just six when Miller entered the league – didn’t have to wait long to experience a little postseason success. But he had an appreciation for Miller’s path and patience.

“It’s terrific. I’m happy for him, for us to be able to help him get there,” Beal said.

Miller no longer has to deal with the ignominy of never knowing what series victory felt like. “I never really tried to think about it. It was in the back of my mind, just sitting over there,” Miller said. “I’m just happy to get this series over with and move on to the next one.”

The Post Sports Live crew looks ahead to the Wizards' next potential playoff opponent, if the team advances against the Bulls. (Post Sports Live/The Washington Post)