The Houston Dynamo seems to have an edge at its new stadium, where the field is more narrow than most. (Eric Christian Smith/GETTY IMAGES)

Each day reveals a fresh challenge for D.C. United. If not a significant injury, it’s a suspension. Sometimes, it’s both at the same time. Autumnal weather one day, winter the next, summery conditions ahead. The playoff venue is set, and then it’s not. Kickoff is delayed, then postponed. Leave town on a train, return on a plane.

United has had to be quick on its feet, on and off the field, to cope with a succession of trials over two months. With the improvisation of a jazz soloist, Ben Olsen’s bunch has adapted to changing circumstances and, in the process, extended the season beyond expectations.

The latest task: Playing the Houston Dynamo on two days’ rest without two suspended starters in the first leg of the MLS Eastern Conference finals Sunday afternoon at BBVA Compass Stadium.

“It’s another obstacle we need to confront,” said Olsen, whose squad is unbeaten in nine straight. “This team has done a good job with it, finding ways to win, but this is a big one.”

It’s big for several reasons. Aside from the absence of goalkeeper Bill Hamid and defender Andy Najar, who are both suspended, United is visiting a city where it has failed to win in nine all-time attempts since 2006 (eight defeats, one draw and an 18-4 scoring deficit).

D.C. will have to adjust to a 48-degree swing in game-time temperatures between Thursday’s rescheduled match in snowy New Jersey and Sunday’s affair in balmy Texas. United hasn’t played in warm, humid air since late August.

And then there are Houston’s narrow field dimensions, a factor in United’s struggles this year. A five-yard difference doesn’t sound like much, but over the length of 115 yards, it impacts the game.

Although the space existed for a standard field (72 to 75 yards wide) when the orange-splashed downtown venue opened six months ago, the Dynamo wanted to retain the size to which it had become accustomed at its previous home, the University of Houston’s Robertson Stadium.

“There are more 50-50 balls, more defending in the box and less room for error,” said Olsen, whose team lost there, 1-0 and 4-0, during the regular season. “Foul up a play in your half, and they’re going to make you pay.

“It’s a tough place to play. We haven’t been great there, but a lot of teams haven’t been great there. If any group can do it, it’s this group. We’ve responded to a lot of tough circumstances.”

The Dynamo was 11-0-6 at home in the regular season with 12 goals conceded and, last weekend, defeated top-seeded Sporting Kansas City, 2-0, en route to a semifinal-series upset.

United, though, has made strides on the road. Since losing six straight, D.C. has gone 3-0-2 away from RFK, capped by a 1-0 series-clinching victory at New York on Thursday.

The other factors working against United? Houston is good, and well coached by Dominic Kinnear. After advancing to the MLS Cup last year, the Dynamo is unfazed by pressure situations.

United, however, does not need to win Sunday. Given the challenges, a draw would suffice and put D.C. in prime position heading into the final leg of the total-goals series next Sunday at RFK Stadium. Since losing to Kansas City in March, Olsen’s squad is 12-0-5 in Washington and compiled the most regular season home points in the league (40).

By winning the conference title, United would host the MLS Cup on Dec. 1 against the Seattle Sounders or Los Angeles Galaxy. (D.C. had the third-highest point total in the 19-team league, and front-runners San Jose and Kansas City have been eliminated.)

Before gazing ahead, United must grind out another result at Houston. Since Dwayne De Rosario went down with a knee injury Sept. 10, the club has become more industrious, deliberate and defensive. United has scored multiple goals only twice in the past nine matches but allowed more than one just once.

Confronted by other recent injuries — left back Chris Korb is recovering from a hamstring ailment — Olsen has patched together a lineup that lacks elegance but works in harmony and exhibits a steeled resolve.

“It’s not just winning games, but the way we’ve done it over the last two months,” club president Kevin Payne said. “We’ve been pretty good all year — it’s not like we were schlubs — but the way we’ve come together is pretty special.”