Calen Carr, who netted the game winner

The Houston Dynamo took advantage of two defensive lapses in the first half, then relied on goalkeeper Tally Hall to edge the Philadelphia Union in the first leg of their MLS Cup Quarterfinal series 2-1.

Philadelphia began the match with a wrinkle. Manager Peter Nowak added defensive midfield specialist Stefani Miglioranzi to the starting lineup, but within the context of the first half he was at the center of a backline 5. This gave the Union extra manpower at the back, but left them hurting in the center of the park, especially because wingbacks Sheanon Williams and Gabriel Farfan were expected to maintain a tight backline when out of possession.

Houston went with a more conventional 4-4-2. The surprise may have been that Honduran striker Carlos Costly was left on the bench in exchange for Calen Carr. Carr paired with Dynamo mainstay Brian Ching. Brad Davis and Danny Cruz played the wings, with Luiz Camargo and Adam Moffat playing deeper holding midfield roles.

The match almost immediately threatened to streak out of control when left back Gabriel Farfan recklessly got his boot into Cruz’ face. In a regular season match, this might have meant an early ejection; in a playoff series, referee Jair Marrufo held back the full force of his authority and only issued a caution.

On the restart, Brad Davis’ free kick from 40 yards was redirected by Andre Hainault past goalkeeper Faryd Mondragon to stake Houston an early lead. The Union have struggled all season in defending set pieces, and this was no exception. With both Miglioranzi and Danny Califf near Hainault, neither could neutralize the run he made.

The Union responded less than two minutes later. The other Farfan brother, Michael, completed a run through the center of the pitch, and chipped a ball over the central defense to an open Sebastien LeToux. LeToux struck the ball swiftly past Tally Hall to knot the score at one.

The remainder of the first half tactically favored the Dynamo. When attacking from the back, the Union had moderate success moving the ball, because Williams and Farfan were free to then move up and provide width. Once the Union ceded possession, the wingbacks moved back into the defensive 5, and that exposed the remaining three in midfield trying to matchup against 4 (5 when Ching drifted back to link play). In general, Houston forced Philadelphia into their own half for most of the first 45 minutes.

The decisive goal came at the half-hour mark. Ching got the ball in the space between Brian Carroll and the backline. The Union backline was trying to hold a good line, and Carr was floating around the central defense. Ching played a through ball to Carr, and Carlos Valdes did not hold the line well enough. The pass was the perfect weight, and Mondragon could not get there before Carr could guide it past him.

The match remained physical and tense throughout. Danny Cruz earned his own yellow, and in the second half could have easily earned his second on a cynical tackle on the outskirts of the area. Marrufo again showed prudence. The resulting free kick was a good one, by LeToux. It found a hole in the wall and looked destined for the net, but what appeared to be a handball by Brad Davis at the 6 yard box was waved off by Marrufo as well. Replays clearly showed Davis wave his elbow to stop the shot, but the referee was convinced it struck his shoulder blade.

Tactically, Nowak asked Miglioranzi to push forward into a central midfielder role after the half. This, coupled with the natural tendency for a road team in the lead to play conservatively, allowed the Union to control second half possession. Philadelphia had countless opportunities to draw level, including a deft header by Jack McInerney which cleanly struck the crossbar. 2nd Half substitute Roger Torres nearly bent a free kick into the top corner, but Hall tipped it away. And in the last throes of the match, Valdes headed a cross up and over Hall, and it looked as though it could go in, but the keeper had just enough height to secure it.

The return leg will be on Thursday night at 8 PM, from Robertson Stadium in Houston.