Several through balls pierced the core of the back line, manned by Eddie Robinson and Patrick Ianni. Arturo Alvarez shot and Onstad saved as Houston sorted out its assignments, and later in the match he epitomized his struggles by taking one ball so far wide of Onstad it nearly reached the endline. Then Alvarez clumsily lost possession.
Dominic Oduro ran onto a threaded Bobby Rhine pass, and Robinson apparently clipped him just inside the box, yet instead of a penalty referee Tim Weyland cautioned Oduro for diving.
Not just the backline should be blamed. Rhine and Dax McCarty occasionally found space unguarded by Ricardo Clark, who played central midfield alongside Dwayne DeRosario with Richard Mulrooney deployed at right back.
Clark had a tougher task at times because Ianni and Robinson weren't in sync stepping forward either to cut off passes or spring the offside trap. With Jaqua playing left mid in place of Stuart Holden, Rhine slid inside him to release passes before Clark could close Rhine down.
Two corner kicks found Carlos Ruiz open, but both times he headed shots straight to Onstad. Who's marking that guy?
FCD, too, must deal with issues. Clarence Goodson marred an otherwise solid game by allowing Clark to skip past him and fire a hard shot that keeper Ray Burse turned away. In the middle Goodson can be imposing but when sliding outside to cover for right back Drew Moor, he's exposed.
Speaking of exposed, the entire left side of the Dallas team seemed to have vanished when DeRosario played a ball wide for Brian Mullan to dribble upfield and drill a hard cross Brian Ching let carom off his chest into the goal.
A minute earlier, a goal by Nate Jaqua had been disallowed by an offside call. This was another narrow decision but Mullan wasn't offside.
And remember those accounts that Mulrooney, traded by Dallas to Toronto before moving on to Houston, had "lost a step?"
In the second half he ran down the speedy Oduro, who had come on as a substitute, when isolated against him on the flank. He's never been a speedy player, anyway, and his experience and versatility may be invaluable down the stretch.