The road to MLS Cup sure looks like it might end at the Home Depot Center once again.

Houston and Los Angeles assumed firm control of their conference championship ties with D.C. United and Seattle on Sunday, and set the stage for a potential rematch in the showcase final on Dec. 1. Nothing is certain as of yet with the second legs still to play, but the two experienced sides sorted out their business at home in a professional manner. Sunday's results strengthened the increasingly persistent questions about the tenuous home-field advantage allotted to higher seeds during the postseason.

Those structural debates will rage onwards this week, but the fallout from both matches will prove more meaningful as all four sides prepare for the decisive return affairs next Sunday.

Houston Dynamo 3 - D.C. United 1 (second leg: Nov 18, at RFK Stadium, Washington)

Houston canceled out Nick DeLeon's early opener with three unanswered goals in the second half to take charge of the Eastern Conference championship. Andre Hainault escaped what looked like a certain sending off in the first half to notch the equalizer six minutes into the second half and spark the revival. Will Bruin and Kofi Sarkodie scored later in the second stanza to provide the cushion heading into the second leg next weekend.

The final result does not adequately reflect the contribution by United in the first half or the tumult caused by a series of injuries and substitutions for both teams. DeLeon's opener - a tidy finish from a rebound created by a quick counter down the left and Lionard Pajoy's shot off the far post - accurately reflected how the gritty visitors started the match. Ben Olsen's side shrugged off the early departures of Chris Pontius (groin) and Marcelo Saragosa (hamstring) to gain a foothold and quell the home side before halftime.

Olsen and his players felt they should have entered the interval with a one-man advantage after Hainault hauled down substitute Raphael Augusto on the stroke of halftime. Replays showed Hainault tugged and scissored Augusto to the ground as the last line of defense, but referee Ricardo Salazar somehow waved away United's cries for a foul. United assistant (and former Houston goalkeeper) Pat Onstad saw red at halftime for dissent.

Houston grasped the reprieve with both hands and equalized when Hainault polished off Boniek Garcia's inviting cross six minutes after play resumed. Bruin tucked home the Dynamo's second from close range after 68 minutes after United goalkeeper Joe Willis pushed substitute Giles Barnes' cross into his path. Sarkodie finished off the second half resurgence with a fine finish inside the back post to give the Dynamo a two-goal lead to take to RFK Stadium next weekend.

United faces an uphill task to overturn the deficit in the second leg. Olsen must address his problem at right back - Houston coach Dominic Kinnear shifted to a 4-3-3 during the match to exploit Robbie Russell's dearth of pace and the tactic yielded significant dividends - and hope the likes of Pontius, Dwayne De Rosario (knee) and Brandon McDonald (calf) recover in time to feature. The boisterous home support will urge United forward, but the cagey Dynamo will hold out earnestly in a bid to secure a second straight MLS Cup berth.

Los Angeles Galaxy 3 - Seattle Sounders 0 (second leg: Sunday, Nov 18, at CenturyLink Field, Seattle)

The defending champions produced a display of real quality to send the Sounders back to Seattle clinging to their championship dreams ahead of the second leg. Robbie Keane opened the scoring just before halftime to invigorate a fairly moribund match. Mike Magee capped off a deft counter for the second goal after 65 minutes before Keane extended the advantage by tapping home Christian Wilhelmsson's effort two minutes later to complete the rout.

It proved no less than the Galaxy deserved on a night that took a little while to get going. Neither side looked particularly potent for much of the first half, though Wilhelmsson impressed on the right flank as he and the Galaxy targeted the suspect left side of the Sounders defense. The opener came from that department shortly before halftime as Franklin crossed from the right wing and Wilhelmsson flicked the ball into Landon Donovan's path. Donovan clipped a perfect ball toward the back post for Keane to deftly head home at the back stick and separate the teams at the interval.

Seattle coach Sigi Schmid told ESPN at halftime that he would be fine with a 1-0 defeat, but his defensive shape did not prove strong enough to deliver upon that request. Los Angeles tore through the Sounders on the counter for the second goal in the 65th minute as a series of neat passes exploited the space allotted by the visitors in midfield and ultimately prompted Magee's tidy finish from close range. Keane completed the scoring after Wilhelmsson chested a deflected Donovan shot toward goal and the Ireland international ensured the ball crossed the line.

Late interventions by Jeff Parke and Michael Gspurning and a wasteful finish by Galaxy substitute Michael Stephens kept a flicker of hope alive for Seattle ahead of the return match. Seattle must name Mauro Rosales in the starting XI (his absence with a hamstring complaint has showed how limited the Sounders are without him) and prod some form of production out of Fredy Montero (zero goals in nine playoff appearances) to mount a furious comeback. Arena will exercise ample caution with Donovan (if his hamstring presents a concern) and his tactics in order to nurse this lead through to a second straight MLS Cup berth.