Neither team posed much of an offensive threat in the first leg in Houston, and it will be all to play for at Sporting Park in two weeks .
With both teams having played 120 minutes in their respective conference semifinals just three days earlier, an exhausting battle with little offense was played out on a sloppy pitch in Houston.
In a cagey first half, the home side was dealt a blow when midfielder Ricardo Clark limped off with a knee injury, and had to be replaced by Andrew Driver. The switch prompted Dominic Kinnear to rearrange his side in a 4-3-3 formation.
Houston came the closest to opening the scoring in the first half, as Boniek Garcia's free kick looked destined for the far corner, only to be kept out by a sprawling save from Jimmy Nielsen.
There were even fewer chances in the second half, as Nielsen and Tally Hall had comfortable afternoons in goal. By game's end, both sides appeared content to walk away with a stalemate and rest up ahead of the second leg.
With the international break looming, the second leg will not take place for two weeks, as the two sides will determine who advances to MLS Cup on Nov. 23 at Sporting Park.