The Philadelphia Union posted their first clean sheet in more than two months last week, although it was more of a side note.

Philadelphia crushed Sporting Kansas City, 4-0, to snap a six-game winless run in MLS. Jack McInerney's brace and the four goals grabbed the spotlight, but a revived defense was an even better sign.

Interim coach John Hackworth believed the defense could be even better.

Philadelphia traded with Vancouver Whitecaps FC to acquire former MLS Defender of the Year finalist Bakary Soumare on Tuesday.

Now, a Union (3-8-2) squad that has struggled all season will try to build on the huge win over Sporting when it visits the Houston Dynamo on Saturday.

"(Defense) been an Achilles heel all year," said Hackworth. "It took a lot of pride in that, and was lead the way by Carlos (Valdes)."

"I hope (the win is) one of many. So I'm not going to get too high. I'm not going to get too low."

Philadelphia has just one win in six road matches this season, but it won both games in Houston last year at Robertson Stadium. Houston earned revenge in the postseason, winning both legs of their Eastern Conference semifinal series.

The Union will be without suspended defender Raymon Gaddis this week, but even without him, Hackworth hopes to build on the win last weekend. Soumare will be eligible to play, but it is unknown if he will step right into the lineup.

Houston (5-5-5) has never beaten Philadelphia in the regular season, posting a pair of losses and a pair of draws. But the two playoff wins are huge. Houston went on to lose the MLS Cup to the Los Angeles Galaxy.

The Dynamo are just fifth in the Eastern Conference this season, 10 points off the top and nine points ahead of ninth-place Philadelphia.

Last season, Houston was winless in its first 15 road matches and it has found that form again this season. After two road wins to start the season, Houston is winless in its last eight on the road.

After a 4-2 loss at the Montreal Impact last week, coach Dominic Kinnear said he accepted the blame for the loss.

"We looked tired and I think that's down to my team selection. Every once in a while the coach has to stand up and say the defeat is on him," Kinnear said.

Houston has not lost at home in five matches, but will need to play better on defense to remain unbeaten (three wins, two draws) at BBVA.

The Dynamo, who will be without suspended Adam Moffat this week, have allowed 15 goals in their last six games. On the year, Houston has allowed 12 goals in the opening 30 minutes of its games.

"This is new territory for the guys that are back there right now," Houston defender Bobby Boswell said. "We've been pretty stingy and I think we've gotten a little loose lately. There's no excuse for it."