Houston lost to UNAM, 3-1, at home last week and with a 1-1-2 (W-L-T) record and five points, needs four more points to pass Firpo, which upset San Francisco FC of Panama, 3-2, to raise its record to 2-1-1 (7 points).
The Dynamo-Firpo match in Houston, originally scheduled for Oct. 7, had to be rescheduled because of Hurricane Ike. It will be played Nov. 26, three days after MLS Cup, but if Firpo wins Tuesday the match will be meaningless and could well be canceled.
Firpo stunned San Francisco with a barrage of goals after falling behind. Dennis Alas tied the game two minutes before halftime, Christian Sanchez put Firpo ahead four minutes into the second half and Patricio Gomez made it 3-1 only two minutes later. The defeat eliminated San Francisco; UNAM has already clinched a spot in the quarterfinals.
Jorge Sanchez and Mauricio Quintanilla are suspended for Tuesday game. No Houston players are suspended, which leaves Coach Dominic Kinnear with all of his options available.
"That's going to be difficult for us, going all the way to El Salvador," said Kinnear. "We've traveled a lot this year with the Champions Cup, SuperLiga and now the Champions League in addition to our MLS schedule and the [U.S.] Open Cup, but for the most part the guys have handled it well, so I'm looking for a big effort in an important game."
On Sunday, Houston plays New York at the Meadowlands in the first leg of their conference semifinal, so Kinnear is hoping to rest at least a few regulars and save them for what will be a rigorous match on artificial turf.
Group C action resumes Tuesday with CD Olimpia hosting Joe Public FC in Tegucigalpa, Honduras, and Montreal facing Atlante in Cancun, Mexico. Atlante and Montreal have clinched advancement.