In their first meeting, the Houston Dynamo scored three times in an hour and beat CD FAS 3-1 at Estadio Cuscatlán in San Salvador on August 22.
A repeat Thursday at Houston's BBVA Compass Stadium would eliminate FAS from advancing to the CONCACAF Champions League knockout stage - and put the Dynamo in position to return to the quarterfinals for the first time since the inaugural championship.
The Dynamo, though, will again be without midfielder Adam Moffat, who has been sidelined with a strained right adductor mucle for more than two months and then aggravated it in a 1-1 Champions League draw against Olimpia on August 30.
Moffat, who scored the 57th-minute equalizer in that match, has returned to training, but he's not quite ready for game action.
"It's feeling better. This week's been good," he told the Houston Chronicle. "It's been good getting out there playing again. It's been a little while. I'm still a little bit cautious. We'll see how it goes the next couple of days. Hopefully we'll play here in the next week or so."
Houston is tied atop Group 3 with Olimpia with four points, although the Honduran side has a slight edge in goal difference. The American club's advantage is that its final two group stage matches are at their sparkling new home.
It has lost only once in 15 games since it opened the $95 million, 22,000-seat building on May 12, a club friendly against Spain's Valencia. It has won nine of the other 14.
FAS, meanwhile, faces an uphill climb without a point from its first two contests, allowing three goals in both losses at Olimpia and at home to Houston.
It has won just one of its last five contests overall, played Santa Tecla to a 2-2 draw Saturday and fallen to fifth in the Salvadoran Apertura standings. Additionally, it has won only one Champions League in 10 tries, is winless in its last eight over the past two years with six losses.
In Group 7, Chorrillo faces the same daunting task as FAS, needing a victory against Municipal to stay in contention for a spot in the knockout stage. Winless in a pair of group stage matches, Chorrillo was three minutes from claiming a home draw against Municipal on August 23, but allowed a late Josimar Arias winner for the visitors from Guatemala.
Two-time defending Champions League champion Monterrey leads the group with six points from two matches, while Municipal is second with three.
Municipal enters Thursday night's match at Estadio Mateo Flores coming off a 1-0 win against Universidad on Sunday thanks to Arias' 72nd-minute winner.
"It was a great result, but now only we think of Thursday's game against Chorrillo," he told Prensa Libre. "We're going to play with all our resources. In addition, we will play to win, because we have the aspiration to move to the next phase."
For Chorrillo, Renan Addles has scored in each of its last three games. But the club hasn't won in over a month, going winless in its last five including a 1-1 draw with Arabe Unido in the Panamanian league on Saturday.