D.C. United honors retiring MLS star Landon Donovan with gifts including an RFK Stadium seat, a photograph from the Oct. 14, 2009 USA vs. Costa Rica World Cup qualifier, and an oar in honor of Donovan's impact on American soccer history. (Danny Moloshok/Associated Press)

The first half proved decisive in each of D.C. United’s matches on this week-long road trip, in both good and bad ways for Ben Olsen’s weary squad. Four days after stunning Kansas City with three goals before intermission, United conceded three in the first 45 minutes to the Los Angeles Galaxy on Wednesday night and absorbed a 4-1 defeat before 16,044 at StubHub Center.

The half began poorly for United (a goal after 67 seconds) and ended badly (a goal in stoppage time). In between, the Galaxy minced United with stylish ball movement, piercing passes and composed finishes.

“We had too many guys have poor nights and I had a poor night,” Olsen said. “If you add that up against the L.A. Galaxy and you are down 1-0 in the first couple minutes, you are in for a long night. It’s pretty simple.”

In his final regular season game against United before retirement, Landon Donovan posted two assists and added a late penalty kick as the Galaxy (12-5-7) continued a late-season surge and pulled within two points of Seattle in the Western Conference.

With a game in hand, United (13-8-4) missed an opportunity to broaden its one-point lead over idle Kansas City in the Eastern Conference.

Sean Franklin rises above Landon Donovan in the first half in Los Angeles. (Harry How/Getty Images)

“They were good tonight,” captain Bobby Boswell said, “and we weren’t. I wish there were an answer.”

Alan Gordon, starting in place of injured top scorer Robbie Keane, scored in the opening moments and Omar Gonzalez and Baggio Husidic added goals before the break. United was credited with an own goal in the 58th minute and Donovan added to his MLS career record in the 75th with his 141st regular season goal.

Before the game, United presented Donovan with an orange No. 10 seat from RFK Stadium, a venue where he bedeviled United several times and excelled with the U.S. national team.

Amid the busiest stretch of the season, Olsen shuffled the lineup in an effort to avoid burning out his regulars. While the defensive corps remained the same, three-fourths of the midfield turned over: Lewis Neal, Alex Caskey and David Estrada were in, Davy Arnaud, Nick DeLeon and Chris Rolfe were out.

Rolfe might have made an appearance if not for an undisclosed injury suffered Saturday. He traveled with the team but did not suit up.

The most intrigue surrounded the frontline. Luis Silva and Fabian Espindola had formed a productive partnership while Eddie Johnson served a two-game MLS suspension, but with Johnson eligible again and a conference showdown looming Sunday against New York in Washington, Olsen sat Espindola.

Gordon scored before the smoke from the pregame fireworks cleared.

Landon Donovan, left, battles D.C. United's David Estrada for possession in the first half Wednesday. Donovan would be assessed a yellow card for his aggressive play. (Danny Moloshok/Associated Press)

Donovan played a through ball to Gordon in a gaping channel. Gordon squared a pass to Marcelo Sarvas. With Sarvas, goalkeeper Bill Hamid and defenders Taylor Kemp and Steve Birnbaum converging in the penalty area, Kemp knocked the ball off Birnbaum and back to Gordon, who fired into an open net for his second goal since arriving from San Jose 2 1 / 2 weeks ago.

It was not the quickest goal conceded by United this season. In May, Portland needed 34 seconds.

By the 20th minute, the Galaxy could have had three goals. Gordon missed the near corner from eight yards and Hamid made a sweet leg save on Gyasi Zardes deep in the box.

United broke in the 25th minute as Gonzalez side-volleyed Donovan’s corner kick. Birnbaum’s marking was not good enough, allowing the 6-foot-5 center back from the University of Maryland to whip his right leg around the rookie and beat Hamid from 10 yards.

“We have got to be a little bit tougher mentality when we go down a goal. We’ve got to be able to deal with it and not collapse,” Neal said. “Coming here was always going to be a tough game, but it was the manner that we got beat that is upsetting to me.”

The early problems were reminiscent of United’s performance earlier this month at Real Salt Lake, yielding three goals in the first half. D.C. was never in that game and was not in this one until the middle of the second half.

Hamid thwarted Zardes’s bid on a swift counterattack in the 38th minute, but in stoppage time, Donovan pushed the ball to A.J. DeLaGarza (Lackey, University of Maryland) charging into the right side of the box. DeLaGarza’s low cross connected with Husidic for a one-timer past the beleaguered Hamid.

Any hopes of a comeback were paralyzed by United’s inability to keep possession. It was as if the Galaxy was playing with a two-man advantage. The halftime statistics showed the Galaxy with 58 percent of possession, but it seemed like a lot more.

With the outcome all but decided, Olsen removed Silva early in the second half and inserted defensive midfielder Jared Jeffrey.

United finally showed some life. In the 58th minute, Caskey delivered a dangerous ball to the six-yard box. As Johnson, goalkeeper Jaime Penedo and defender Leonardo congregated, the ball skipped into the net. Initially credited to Johnson, the score was later switched to an own goal on Leonardo. The league is likely to review video of the play again this week.

Perhaps sensing hope, Olsen turned to Espindola and later to DeLeon. United threatened to pull closer, but Penedo made two quality saves.

Hamid kept United in the match with two terrific stops, but Donovan converted a penalty kick after referee Kevin Stott made a baffling call against Birnbaum defending Gonzalez on a corner kick.

“If we don’t play up to speed, if we are not all on the same page and focused on every play and squeezing every ounce of talent out of our team, we are not good enough,” Olsen said. “That is who we are. We get reminders every now and then, so tonight is a reminder. But they are a good team and they are very well coached, so sometimes this happens on the road. To come here and get a result, you need everybody and then you have a chance.”