The Dynamo were without six-time Major League Soccer All-Star midfielder Brad Davis, who missed his third straight match with a sprained right ankle.
If the Dynamo missed Davis, though, they certainly did not let on in the first half. Houston struck 12 shots at Union keeper Zac MacMath's goal and forced him to make two saves. It also earned three corner kicks in the first 45 minutes and had the Union pinned in PPL Park's River End for most of the half.
Union boss John Hackworth's team talk during the interval must have gotten through, though, because the Union seized control of the match throughout the second half. Unfortunately for the Union fans among the more than 17,000 in attendance, though, a winning marker never came.
The match essentially turned on two plays.
Dynamo forward Will Bruin crashed a right-footed shot off the post past MacMath in the 38th minute. Had the Dynamo scored there, no vivid imagination would have been needed to imagine them getting another goal before the break. The Union were running around in the defensive area without direction.
Having survived the first half, though, the Union will look back at the second half as an opportunity wasted.
New Union acquisition Andrew Wenger had the two best scoring chances of the second half for either side.
In the 52nd minute, Wenger poured down the left wing with the ball and half an acre of open space between him and Dynamo keeper Tally Hall. Inexplicably, though, with an awful lot of net to shoot at, Wenger picked out an onrushing Conor Casey instead of shooting.
Casey's shot was blocked, and the chance went begging.
Before Wenger's second big chance, though, the Union were given an enormous gift.
Dynamo defender Kofi Sarkodie, playing on a yellow card from the 40th minute on, took too long to deliver a defensive zone throw-in and received a second yellow card in the 82nd minute, leading to a red card and his dismissal.
That decision can only be called harsh, and it seemed perhaps that the referee gave Sarkodie the yellow card for time-wasting without realizing what the consequence would be.
Fortunately for Sarkodie, the Dynamo tightened the defensive screws through the final seven minutes of regulation and six minutes of stoppage time.
Wenger had the ball fall to him in front of Hall's goal, but his shot flew just over the bar.
The MLS season, like so many professional sporting seasons, is interminable. The Union will be playing until the end of October in search of a playoff berth.
If they miss the playoffs again this season, though, they will surely look back on this 0-0 result with a nearly quarter-hour man advantage as a gift-wrapped chance lost.