WASHINGTON (Map, News) - Zach Wells knows Pachuca isn’t invincible. The former Dynamo goalkeeper saw his old team score against them twice in each of two visits to Houston’s Robertson Stadium last year.

It’s an encouraging sign for D.C. United, which enters the second leg of their CONCACAF Champions’ Cup semifinal against Pachuca, the tournament’s defending champion, with the massive task of overcoming just that kind of deficit after last week’s 2-0 defeat in Mexico.

“They’re definitely a really respectable team, obviously, from the way I’ve seen them play firsthand the last two years,” said Wells, who is expected to make his fifth consecutive start for United. “But I think we can play with them, and I think we can beat them at home like we did last year with Houston.”

United needs to win by three goals to advance to the Champions’ Cup final. If the two teams are tied on aggregate after regulation, they’ll play two 15-minute overtimes, and if tied after that, will then have a penalty shootout.

The Mexican squad will contend with travel and a short turnaround, having played a league match Sunday. It could lead Pachuca head coach Enrique Meza to adopt a conservative approach while United expects to come out flying as they did in last weekend’s 4-1 thrashing of Toronto, when they scored twice in the first five minutes.

Hitting the back of the net quickly at home has become a regular occurrence for D.C., which last year scored in the 16th minute or earlier in nine different matches in all competitions.

“I think our guys respond well to being at home,” said United head coach Tom Soehn. “When you have so many new guys, it takes a while to get a road mentality so obviously coming home is a good thing. Just looking at that sign [inside RFK Stadium], ‘Home of the 12th Man,’ I think that’s such a huge advantage because our fans are awesome.”

Soehn said forward Jaime Moreno continues to make strides to return to full fitness following a hamstring injury. Santino Quaranta also is in a cast for a broken right hand after it was stepped on early against Toronto, but he isn’t expected to miss any action.