D.C. United was defiant that inexperience wasn't the cause of the unfortunate incidents that led to a 1-1 draw in the opener of its two-game Eastern Conference semifinal playoff series with the New York Red Bulls.

But it couldn't have been a coincidence that a missed penalty kick, a goalkeeper fumble that led to a goal and an unnecessary red card each happened to a United player taking part in his first postseason match before an inspired crowd of 17,556 that filled RFK Stadium on short notice.

"We tied New York 1-1," United coach Ben Olsen said. "A pretty good team. They've got some pretty good players, a pretty good attack. Looking at the game, I didn't think they had very many chances at all. I don't think it was inexperience."

Olsen said fourth-year midfielder Chris Pontius, carrying a team- and career-high 12 goals into the playoffs, "had his best game in months." But Pontius also had a penalty kick saved in the 33rd minute by Red Bulls goalkeeper Luis Robles, who dove to his right to parry a shot that could have been better.

"I stepped up, doing what I normally do on a PK," Pontius said. "I just missed it. A good save. I'd like to obviously put it up a little bit higher, get it away from him. But I gotta have a short-term memory."

The miss didn't detract from a dominant first half in United's first playoff game since 2007. Chris Korb tested Robles in the third minute with a pinpoint one-timer to the far post that was denied. Moments after his penalty miss, Pontius' header across the box was redirected just wide by Branko Boskovic.

"Did you see any inexperience out there tonight?" Pontius said. "I thought we played pretty well. I think the guys are ready. They're juiced for the game on Wednesday."

United finally went in front courtesy of a New York error in the 61st minute. Korb's cross from the left side was turned into the net at the near post by sliding Red Bulls defender Roy Miller, who had United midfielder Nick DeLeon right behind him.

But the lead was given right back four minutes later when Bill Hamid fell into the net with the ball trying to handle a seemingly routine header. But the third-year goalkeeper couldn't believe there was no whistle from referee Jair Marrufo for a nudge he had received from New York defender Markus Holgersson as he tried to elevate for the ball.

"I got bumped. That's what went through my mind," Hamid said. "The ball was headed by Heath [Pearce], it came back in the air, and then Holgersson bumped me. He knew I was about to jump. He knew I was going to come up for that. I was inside the six, and he decided to bump me right before my jump. I guess that's not a foul."

But Hamid's fellow homegrown United star, Andy Najar, had no excuse for the ejection that forced his team to play short-handed for the final 20 minutes. Marrufo already had a yellow card out for Najar's trip of Joel Lindpere. But when the 19-year-old, jogging away with the ball, turned to throw it back, he hit Marrufo, drawing a red card. It comes with a one-game suspension that will deny United the presence of one of its most dynamic players when the teams meet in the second half of the total goals series.

"My intention wasn't to throw the ball at the referee," Najar said through an interpreter. "I just turned around and threw the ball back, and unfortunately the referee was there and the ball hit him. ... Whoever steps in for me in the next game I'm sure is going to do a great job."

Olsen took the call in stride, preferring to focus on the opportunities created by his own team and the stifling defense that allowed just two shots on goal, including just one from Thierry Henry. But United, having already ceded home-field advantage when the order of games was switched because of the impact of Hurricane Sandy on the New Jersey and New York region, now must win at Red Bull Arena on Wednesday to advance to the conference finals.

"A young kid and he made a young mistake," Olsen said. "... But we'll adjust. That's what we've been doing all year, and now we won't have our right back, but we'll respond. It's a beatable team. We should've won this game tonight."