Do or die match against Árabe Unido prepares Houston Dynamo for similar situation against D.C. United

A century ago the United States completed the Panama Canal, a miracle of engineering that is still one of the most important shipping lanes in the world.

Tonight the Dynamo play the club from the city at the canal's northern entrance. Like the vessels just a couple of miles from Colon, the team is seeking safe passage, a straightforward way through on a long and difficult journey.

Draw or win against Árabe Unido (7 p.m. CT; FOX Soccer Plus) in their final group stage match and the Dynamo will advance to the knockout rounds of the CONCACAF Champions League. That would be a worthy achievement, but no matter the significance of this evening's game it is impossible not to view it in the context of the looming, season-defining MLS encounter with D.C. United on Sunday.

Tonight, it's all down to the Dynamo: avoid defeat and they will go through at the expense of their opponents. Simple. Come the weekend, though, Houston will not only have to take care of their own business but require a little help from an Eastern Conference rival.

Last Sunday's 3-0 defeat to the New York Red Bulls, coupled with other results, snatched control of their playoff ambitions out of the Dynamo's hands. It was a sudden, surprising shift off course for a team that had been steadily navigating in the right direction in the past few weeks.

And now the knowledge that the D.C. fixture is all-important makes the Árabe Unido game that bit trickier, that bit more stressful. But it is also an opportunity.

Given the tiring travel schedule and risk of picking up injuries, Dominic Kinnear is not likely to field many of the players who started against New York. But that will give those who do play a window to impress the head coach ahead of the D.C. game.

The likes of Andrew Driver, Servando Carrasco, Omar Cummings and Alexander López have logged limited minutes lately but each will feel he could be a difference-maker in RFK Stadium. Some extended match practice tonight should be a welcome warm-up.

Squad depth has been a frequent mantra for the Dynamo this season and the game—being played at the Estadio Agustin Sánchez, near Panama City—will test that theme. Back in August, Houston battled to a 2-1 win over Árabe at BBVA Compass Stadium with a pair of goals from Cam Weaver.

Then there is a potential confidence boost for a club hurting from Sunday's defeat, provided the Dynamo can produce a convincing performance and secure the required result in what could be a tricky environment.

As defender Kofi Sarkodie said after the New York loss: "We need to make sure we go in with a positive mentality against D.C., that's first and foremost."  Entering the weekend's match on the back of a win, even in a different competition with a changed line-up, would surely help.

There was some potential good news on Wednesday night from Utah, as Real Salt Lake concluded their regular season with a 2-1 win over Chivas USA. That lifted RSL to the top of the Supporters Shield standings, above the Red Bulls on tiebreakers.

So New York know they are sure to miss out on the top spot (which guarantees hosting MLS Cup should they make it to the final) if they lose at home to the Chicago Fire on Sunday. And anything less than a win for the Fire, Montreal Impact or New England Revolution opens the door for the Dynamo to rise back into the playoff places.

Speaking after Sunday's loss, center back Bobby Boswell pledged a week of hard work from the team to prepare for two contrasting fixtures—one a trip into relatively unknown territory, the other a voyage into very familiar surroundings.

 "We're going to grind, try to go get a result down in Panama. It's probably going to be hostile and you never know the conditions," said Boswell. "All you can really control is yourself and that's what we're going to work on. And obviously with D.C. it's going to be the last regular season game. We just want to make sure that's not the last game of this 2013 season."

Tom Dart is a contributing writer to Former editor and reporter for The Times of London, Dart currently freelances for The Guardian and